Course of Science Std VII: L –NO 1 , 2 , 4 , 5 , 7 ,8 , 9 , 10 , 11, 13 Std VII 2 Semester Paper Style Marks Q- 1 MCQ. ( 20 ) Q-2 True or False ( 5)Q -3 Answer in one sentence ( any 10) ( 10 ) Q -4 Classify ( 3) Q -5 Give Reasons ( any 3 ) ( 6) Q – 6 Answer In short ( any 6 ) ( 12) Q - 7 Answer in detail ( any 4 ) ( 12)Q -8 Difference ( Any 3 ) ( 9) Q -9 Experiment (any 1 ) ( 3) Science Assignment Ex-1 MCQ’SL – No 1

1) Which appliance uses electrical energy ?A Stove B Solar Cooker C Tube Light D Chullah

2) Which appliances produces electric current ?A Torch B Electric Bulb C Electric Motor D cell

3) Which substances is a electrical conductor ?A Aluminum B Chalk C Rubber D Plastic

4) Which substances is an electrical insulator ?A Rubber B Iron C Copper wire d Alunimium L – No 2

5) What is the force applied to do work in a lever called ?A Load B Effort C Effort Arm D Load Arm

6) What is the end of a lever using which work is done known as ?A Effort arm B Load Arm C Load Distance D Effort

7) Which of the following is a lever of the first type?A Nutcracker B. Tongs C. Scissors D. Broom

8) What type of lever is nutcracker?A First B. Second C. Third D. None of the given

9) What type of lever is pincers?A. First B. Second C. Third D. None of the given

10) Whose position in the middle in scissors ?A Effort B Fulcrum C Load D Any one of the given

11) What is the type of lever in which load is in the middle ?

A First B Second C Third D Cannot be said definitely 12) What is the type of lever in which effort arm is in the middle ?

A First B Second C Third D Cannot be said definitely 13) where is the position of load in nutcracker ?

A At one end B At the other end C In the middle D Any where 14) Which of the following is the lever of third type ?

A Tailor scissors B Lemon squeezer C Balance D Fishing Hook L-4

15) Which is the standard unit of mass?A Liter B Kilogram C Newton D Cubic meter

16) By which symbol is the mass of a substance denoted?A m B V C W D N

17) Which instrument is used to measure the mass of a substance?A Spring balance B Measuring cylinder C Physical balance D Burette

18) Which unit is used to measure weight?A Kilogram B Gram C Liter D Newton

19) Which instrument is used to measure the weight of a substance?A Spring balance B Burette C Beam balance D Measuring cylinder

20) Which unit is used to measure the volume of a liquid?A. Meter B Liter C Kilogram D Newton

21) Which instrument is used to measure the volume of a liquid?A Beam balance B Measuring cylinder C Spring balance D Weights

22) By which symbol is the gravitational acceleration denoted?A Kg B G C g D m

23) Which physical quantity is used to compare heaviness or lightness of different substances?A Density B Volume C Weights D Mass

24) The density of which substance is less than water?A Iron B Glass C Ice D Sea WaterL-5

25) If the angle of incidence of an incident ray on a plane mirror is 40°, what will be the angle of reflection?A 20° B 40° C 50° D 80°

26) What is the distance between an object kept 20cm in front of a plane mirror, and its image?A 20 cm B 30 cm C 10 cm D 40 cm

27) What type of image is formed by a plane mirror?A Virtual and erect B Virtual and inverted C Real and inverted D Real and erect

28) Which letter, when kept in front of a plane mirror, is read as it is?A K B E C N D H

29) If the angles between two plane mirrors is 40°, how many images are formed of an object kept between them?A .10 B .9 C .7 D .8

30) What should be the angle between two plane mirrors to get 5 images of an object?A 60° B 72° C . 90° D . 120°

31) . At what angles are the two plane mirrors arranged in a periscope?A. 30° B. 45° C. 60° D. 90°

32) Which instrument works on the principle of images obtained by multiple reflections?A. Periscope B. Kaleidoscope C. Telescope D. MicroscopeL-7

33) Which of the following is an element?A. Sugar B. SaltC. Oxygen D. Air

34) . Which of the following is a compound?A. Copper B. Hydrogen C. Water D. Air

35) Which of the following is a mixture?A. Salt B. Sugar C. Salt solution D. Iron

36) Which of the following is not a compound?A. Sugar B. SaltC. Water D. Gold

37) What is the symbol of magnesium?A. Mg B. Mn C. Ma D. Me

38) What is the constitutional unit of a compound?A. Atom B. Molecule C. Mixture D. Element

39) Separate the one which differs from the others.A. Air B. Water C. Soil D. Mixture of rice and pulsesL-8

40) Which of the following organs has cartilage?A nose B ribcage C Head D heart41 How many bones are there in head?A 8 B 14 C 22 D 2542 How many bones make up ribcage?

A 14 B 24 C 25 D 3343 How many bones make up vertebral column?A 24 B 25 C 31 D 33 4 5 What is the Vertebral made up of?A pectoral girdle B vertebrae C pelvic girdle D Ligment46 In which organ are involuntary muscles present?A hand B leg C neck D heartL-947 What is the degree of hotness or coolness of a substance called?

A. Heat B. Energy C. Temperature D. Transfer of heat.48 What is the temperature of a human body?

B. 37℉ B. 98.6℉ C. 98.6℃ D. 96.8℉49 At what temperature does the water boil?

A.0℃ B. 37℃ C. 39℃ D. 100℃50 At what temperature does water convert into ice?

C. 0 ℃ B. 37℃ C. 98.6℃ D. 100℃51 Which liquid is generally filled in a thermometer?

A. Water B.Kerosene C.Mercury D.Petrol52 What is the unit of temperature?A Newton B. Degree Celsius C.Mercury D.Petrol53 100℃ equals how many ℉ ?

A.32℉ B.98.6℉ C.180℉ D.212℉L-10

54 Which gas is released by living beings during exhalation?A Oxygen B Carbon-dioxide- C Ozone D Hydrogen55 Pollutants in which form are more in the atmosphere?A Solid B Liquid C Gaseous D All of the given56 Which poisonous and foul smelling gas is the atmosphere causes greenhouse effect?A Carbon dioxide B Carbon monoxide C Hydrogen sulphide D Sulphur dioxide57 Increase in the proportion of which gas in the atmosphere causes greenhouse effect A Oxygen B Hydrogen C Ozone D Carbon dioxideWhich gas is responsible for acid rain?58 A Sulphur dioxide B Carbon monoxide C Ammonia D Hydrogen

L-1159 What is the sun?

A Planet B Satellite C Star D Comet60 Which of the following planets does ot have a satellite?

A Mars B Mercury C Saturn D Uranus61 Which is the most brightest planet in the solar system?

A Mars B Jupiter C Venus D Saturn62 Which planet of the solar system appears red?

A Mars B Jupiter C Venus D Saturn63 Which is the largest planet of solar system?

A Mars B Earth C Jupiter D Saturn64 Which celestial body is known as ‘shooting star’?

A Satellite B Meteor C Asteroids D Comet65 Which celestial body is known as ‘tailed star’?

A Meteor B Asteroids C Sun D Comet66 What is the periodicity of the comet Halley?

A 30 days B 365 days C 76 years D 850 years67 When was comet Halley last seen?

A 1916 A.D. B 1910 A.D. C 1986 A.D. D 2004 A.D.68 Between the orbits of which two planets lies the belt of meteorites?A Mercury and Venus B Earth and Mars C Jupiter and Saturn D Mars and Jupiter

L – No 12 69 Which is the ‘national animal’ of India?A. Lion B. Tiger C. Elephant D. Cow70 Where is the lion sanctuary located in India?A Sunderbans B. Gir Forest C.Bharatpur D.Mangrove.71 Where is the wild ass seen?A. Gir forest B . Rann of Kachchh C. Bharatpur Sanctuary D. Sunderbans Sanctuary72 . Where is the albino {white} tiger found in India?A Madhya Pradesh B. Gir forestC. Velavadar D. Rann of Kachchh73 . Which of the following birds is called the ‘sweepers of nature’?A. Indian Crane B. Kite C. Bustard D. Woodpecker74 . Which of the following is a beautiful bird?A. Hawk B. Sparrow C. Pigeon D. Bulbul\Q-2 True or False: L-11 Cell is a device using electrical energy. False .2 Our body is an electrical conductor. True.3 A wire which cannot melt easily is used in a fuse False.

4 Electrical appliances in a house are connected in series in the electric circuit False.L-2 5) Lever is a type of simple machine. true6) Seesaw is the lever of a third type. false7) More load can be lifted with less effort in the lever of third type. false8) The position of effort in a nutcracker is between the load and the fulcrum. false9) The fulcrum in the lever of the first type is between the load and effort. TrueL-410] The weight of a substance remains the same everywhere. False11] The magnitude of mass of a body remains the same everywhere. True12] The more the quantity of matter of a substance, the less is its mass. False13] The gravitational force acting on a substance is called its volume. False14] The body having more density then water sinks in water. TrueL-515) The angle of reflection of a ray of light perpendicular to a plane mirror is 90°.False16) The image form by a plane mirror is always in front of the mirror .False17) Two plane mirrors are kept in kaleidoscope. FalseQ – 3 ANS IN ONE SENTENCE L-1

1) What is required to switch on a radio?A1 Electrical energy is required to switch on a radio2) Why does a bulb is illuminate when it is switched on?A2 When the switch is on electric circuit is closed and the bulb illuminate due to electrical energy .3) From which source does the torch bulb get electrical energy?A3 The torch bulb get electrical energy from the dry battery or cell used in it.4) Which electric appliance remains on for some time even after the electric

power is cut off?A4 The red light of T.V. mobile VCR DVD etc remains on for some time even after the electric power is cut off5) Is the electric circuit is completed or not when we switch on the fan?A5Yes the electric circuit is completed or not when we switch on the fan6) In which type of electric circuit does the electric current not flow?A6 in open electric circuit the electric current not flow7) Name four electrical conductors.A7 Silver, copper, iron and aluminum are four electrical conductors.8) What type of wire is used in a fuse?

A8 A s mall thin conducting wires having new meeting point in used in fuse.9) Four bulbs are connected in parallel with a battery in a closed circuit .what

will happen if one of the bulbs blows out?A9 Even if one bulb blows out other bulbs give light .10) What should Done to activate the blown out fuse?A10 Remove the blown fuse wire and tie a new fuse wire.L-211) What is an effort arm?Ans. The part of the lever between the fulcrum is called an effort arm.12) Whose position is in the middle in tongs ?Ans. Fulcrum and load position is in the middle in tongs.13) What is the type of lever, in which the fulcrum is in the middle

called?Ans. In the lever of first type the fulcrum is in the middle.14) Where is the fulcrum in a pincers?Ans. The fulcrum is in the middle in pincers.15) What type of lever is tongs?Ans. Tongs are third type of lever.16) Where is the position of load in the lever of first type?Ans .The position of the load in the lever of the first type is at one end.17) Whose position is in the middle in the lever of the first type?Ans. The position of fulcrum is in the middle in the of the lever of first type.18) Give an example of the lever in which load distance and the effort

distance is equal?Ans. In the beam balance the load distance and the effort distance is equal.19) What type of a lever is a broom?Ans .Broom is a third type of lever.20) In which type of lever is the load distance always greater than the

effort distance?Ans. In the third type of lever the load distance is always greater than the effort distance.21) In which type of lever can more load be lifted with less effort?Ans. In the lever of second type of lever can more load be lifted with less effort.

L-422) What is the quantity of material in a substance called?Ans The quantity of material in a substance is called mass.

23) What is the force of gravity acting on a substance called?Ans The force of gravity acting on a substance is called weight.24) By which symbol is the weight denoted?Ans W is the symbol of weight denoted.25) The mass of Jay is 30 kg .What is his weight on the earth?Ans The mass of Jay is 30 kg his weight on the earth could be 30kg26) What is the weight of an object on the moon ,if its weight is 60N on

the earth?Ans The weight of an object on the moon is 10 N if its weight is 60 N on earth. 27) Which is the standard unit of volume?Ans The standard unit of volume is cubic cm28) Which is the appliances are used to measure the volume of irregular

shaped substances?Ans The appliances are used to measure the volume of irregular shaped substances are measuring cylinder, displacement vessel.29) How many cubic cm is equal to 1 cubic cm?Ans 1 cubic cm=10,00,00 cubic cm30) What is the ratio of mass to volume of a substance called?Ans The ratio of mass to volume of a substances is called density31) Write the formula to find the density of a substance?Ans The density of a substances=mass/volume32) State the density off water with unit.Ans The density of water with unit is gm/cubic cm ,kg/cubic m

L-533) .What is the reflection of light?Ans. The Phenomenon of ray of light coming back after getting incidence on the surface of object is known as the reflection of light.34) What is regular reflection?Ans. Parallel rays incidence on polished surface gets reflected parallel. Such reflection is known as uniform reflection or regular reflection.35) What type of reflection is the reflection of light from a flat and

smooth surface?Ans. Regular type of reflection is the reflection of light from a flat and smooth surface.36) . What is the angle of reflection, if the angle of incidence is 50°?Ans. 50° is the angle of reflection, if the angle of incidence is 50°.

37) . How many images of an object are formed, if the angle between two plane mirrors is 20°?

Ans. No. of images= 360° - 1=Angles between 2 mirrors=360° -1 ÷20=17 images are formed.

38) . Which type of image cannot be taken on screen?Ans. Virtual type of image cannot be taken on screen.39) . On what principle does the periscope work?Ans. Periscope works on the principle of reflection of light by plane mirror.40) . On what principle does the kaleidoscope work?Ans. Kaleidoscope works on the principle of multiple reflection by plane mirror forming many images.41) . Which instrument is used to observe the steamer on the surface of

sea from the submarine under water?Ans. Periscope is used to observe the steamer on the surface of sea from the submarine under water.42) . At what angles are the three plane mirrors arranged in the

kaleidoscope?Ans. The three plane mirrors in the kaleidoscope are arranged at 60°.

L-743) What is the basic unit of a substance?Ans: The basic unit of a substance is an atom.44) . What is the constitutional unit of an element?Ans: The constitutional unit of an element is an atom.45) . What is the symbol of helium?Ans: The symbol of helium is He.46) . What happens when a strip of magnesium is burnt in air?Ans: When a strip of magnesium is burnt in air we get ashes of white colour. It is magnesium oxide. Magnesium burns with a bright flame.47) . Of which two elements is water composed?Ans: Water is made up of hydrogen and oxygen.

L-848 Of what is skeleton formed?Ans Skeleton is made up of different bones.49 Which structure protects the brain ?Ans Skull protects the brain.

50 Bones of which parts are included in the bones of the head?Ans Bones of skull and face are included in the bones of head.51 By which type of joint are the bones of the skull connected ? Ans The bones of the skull are connected with immovable joints.52 How many pairs are there in the ribcage ?Ans 12 pairs of ribs are there in the ribcage 53 Which structure protects the heart and the lungs?Ans Ribcage protects the heart and lungs54 which organ of the body is protected by the vertebral column?Ans Spinal cord is protected by the vertebral column.55 Where is the spinal cord located?Ans Spinal cord is located in the vertebral column of the body.56 Which is the longest and shortest bone of the body?Ans Thigh bone is the longest and strongest bone of the body.57 How many bones together make up the skeleton of the body?Ans 213 bones together make up the skeleton of the body.58 What is a muscular system?Ans the system which consists of different muscles of the body is known as muscular system.L-959 What happens when hot tea is kept in the open?Ans: When hot tea is kept in the open it releases heat in atmosphere and becomes cold after sometime.60 What happens when a cold substance is kept in the open?Ans: When a cold substance is kept in the open it absorbs heat from the surrounding.61 What is thermal energy?Ans: The total kinetic energy of the atoms of an object is its thermal energy.62 Which has more heat, the water in a pond or the hot tea in a cup?Ans: The hot tea in a cup has more heat because its mass is less so thermal energy is more.63 What is the effect on the temperature of a body when heated?Ans: When a body gets heated its temperature increases.64 Which instrument is used to measure the temperature of a substance?Ans: Thermometer is used to measure the temperature of a substance.65 Which instrument is used to measure the temperature of a patient?Ans: Clinical thermometer is used to measure the temperature of a patient.

66 What is the unit of temperature?Ans: Degree Celsius and Degree Fahrenheit is the unit of temperature.67 What is the boiling point of pure water?Ans: 100℃ is the boiling point of pure water.68 What is the melting point of ice?Ans: 0℃ is the melting point of ice.69 What range of temperature can be measured by a clinical thermometer?Ans: 37℃ and 42℃ is the range of temperature by which a clinical thermometer.70 At which digit is there a red mark in the clinical thermometer?Ans: There is a red mark in the clinical thermometer at 98.6℉71 When can it be said that a person has fever?Ans: Increase in body temperature indicates that person has fever.72 0℃ equals how many℉?Ans: 0℃ equals to 32℉

L-No 1073 What is Air Pollution?Ans The process of air becoming impure and harmful to the living beings is called air pollution.74 What is the proportion of carbondioxide in the atmosphere?Ans The proportion of carbondioxide in the atmosphere is 0.03% .75 What is the cause of spreading harmful radiations in the atmosphere?Ans In the present time, atomic energy is used in different works and so radioactive pollution has increased .76 what is the adverse effect on plants due to air pollution?Ans There is decrease in growth of leaves ,flowers and fruits of plants.77 How does sunlight help in reducing air pollution?Ans The micro-organisms present in the air are killed by heat of the sun and so air becomes pure.78 Which gas is used by Green plants during photosynthesis and which gas is released?Ans Green plants uses carbon-dioxide and release oxygen during photosynthesis.79 Write the full form of PUC?Ans The full form of PUC is Pollution Under Control.L-1180. Which planet is nearest to the sun?Ans. Mercury is a planet nearest to the sun.. 81 Which planet of solar system is known as ‘morning star’?

Ans. Venus is known as ‘morning star’..82 How many times is Jupiter larger than the earth?Ans. Jupiter is 1317 times larger than earth. 83 Which is the most beautiful planet of the solar system?Ans. Saturn is the most beautiful planet of the solar system.. 84 Which planets cannot be seen with unaided eye?Ans. Uranus and Neptune cannot be seen with unaided eye.85 Which planets do not have satellites ?Ans Mercury and Venus are planets which do not have satellites.86 Which two planets are nearer to the Earth?Ans Mars and Saturn are two planets nearer to the Earth.. 87 Which is the satellite of the Earth?Ans Moon is the satellite of the Earth.88 Which planet is farthest from the sun?Ans Pluto is the farthest planet from the sun.89 . Which planet in the solar system is known as ‘Dark planet’?Ans Pluto is known as the Dark planet in the solar system.L-NO 13 90 . For whose protection and breeding is the ‘Sunderbans Sanctuary’ established in West Bengal?Ans: ‘Sunderbans Sanctuary’ in West Bengal is established for the protection and breeding of tigers.91 Which animal is known as the king of the forest?Ans: Lion is known as the king of the forest.92 . Which bird is always seen in the pair of male and female?Ans: Indian Crane {Sarus} is always seen in the pair of male and female.93 . Which fish is called ‘Maghra’ by the Gujarati fisherman?Ans: Whale Shark is called ‘Maghra’ by the Gujarati fisherman.94) . Where is the biggest aviary of India situated?Ans: The biggest aviary of India is situated at Indroda Park Sanctuary in Gandhinagar.Q -4 Classify 1) Electrical conductors and Electrical Insulators : iron key, pin, wood, leather, aluminum wire, rubber, copper rod, ebonite, plastic, silver, our body, brass, wool, match, thin stick of graphite.Electrical conductors = iron key, pin, aluminum wire, copper rod, silver, our body, brass , Thin stick of graphite

Electrical insulators = wood, leather, rubber, ebonite, plastic, wool, matchL-22) Classify into lever of first, second and third type: tailor’s scissors, nutcracker, pincers, tongs, seesaw, beam balance, lemon squeezer, broom, oar of a boat, fishing hook.1) Levers of the first type :-Tailor’s scissors ,pincers ,seesaw, beam balance.2) Levers of second type :-nutcracker , lemon squeezer ,oar of boat .3) Levers of third type :- tongs , fishing hook, broom L-No 4 3) Classify into the units of mass , weight , volume Kilogram , newton , liter , quintal , cubic meter , cubic cm , ton , milliliter Units of Mass - Kilogram , quintal , gram ,ton Units of Weight - newton Units of Volume - liter , cubic meter , cubic cm , milliliter L-No 7 4) Classify into element , compound , mixture

Air, water, iron, oxygen, soil, carbon dioxide, sugar, brass, silver, magnesium, sherbat, sulphur, salt, sodium, solution of glucose.

Elements: iron, oxygen, silver, magnesium, sulphur, sodium.

Compounds: water, carbon dioxide, sugar, salt.

Mixtures: air, soil, brass, sherbat, solution of glucose.

Q- 5 Give Reasons L-No 1 1) 1 A fuse is kept in the domestic electric circuit …. There are changes of the electric current exceeding in the circuit .This damages electrical appliances. If a fuse wire is kept in the circuit, it melts due to excss of current and the circuit becomes open. Current stops flowing in the circuit . Electrical appliances are prevented from damage .Hence, a fuse wire is kept in electric circuit in the house.

L-No 2

2 In tailor’s scissors the length of blades is kept more than that of the handles…. So that load distance becomes more than effort distance. So on applying force on handles, handles move less but blades move more distance . So more length of cloth is cut quickly and the speed of work increases.

3 In scissors for cutting metal sheet the length of handles is kept more than that of blades…… so that the effort distance becomes more than the load distance and work can be done with less efforts. Thus the cutting of metal sheet can be done with less effort.L-No 44 the physical balance used in the laboratory is kept in a glass box ….. so that there is no effect of breeze or breathe.5 an iron piece sinks in water, but the ship made of iron floats on water… because density of iron is more than water. Space occupied by ship is more than its mass. Density of ship is less that that of water, so it floats on water.L-No 8 6 Children should develop the habit to sit straight because their bones are soft. They get bent easily if child does not sit straight. There is a possibility that the child would become humped. Hence children should develop the habit to sit straight.7 Bones are necessary for the body because 1 give shape and support to the body.2 bones give strength and firmness to the body. 3 We can perform movement and locomotion, stand up and sit down and stand erect because of bones.8 Vertebral column is elastic because the vertebral column has cushion like structures between each vertebrae and its ‘s’ shaped arrangement makes it flexible. The cushion like structure is a disk shaped cartilage present between two successive vertebrae which makes elastic.L-No 9 9) Clinical thermometer cannot be used to measure the temperature of boiling water – because water boils at 100℃∧clinical thermometer can measure upto 42℃. So if the clinical thermometer is dipped in boiling water the mercury may expand and the bulb gets breaked.

L- No 10 10 Factories and mills should be established away from residential areas because factories and mills continuously release poisonous gases. The air is polluted and we may suffer from various disease if we inhale such gases.11 Trees should be planted surrounding our residence {1} They absorb Co2 and release O 2 and thus reduce pollution .{2} Trees give out moisture during transpiration and makes the environment cool. {3} Trees stop soil erosion .{4} Trees help in bringing rain L-No 11

12 .Life is not possible on Mercury: because(1)It has no atmosphere. (2)It is the hottest planet (3)It has large difference between day and night temperature.Q – 6 Answer in shortQ1 What are closed and open electric circuits?A1 If both the ends of cell are connected at the different ends of the bulb using conducting wire , then such closed path is known as close circuits. If one of the ends of the bulb or cell is disconnected then such a circuit is known as an open circuit. Q2What is the use of a switch in an electric circuit?A2 A switch is used to make an open circuit or close circuit by off or on state.Q3 When there is a problem in a light or fan in one room at home, the lights and fans in the other rooms remain on. Why does it so happen?A3 At home, electrical appliances are connected in parallel in the electric circuit. There is a separate electric circuit for each appliance in parallel connection. When there is a problem in an appliance, the circuit connected to it breakes and electric current stops flowing in the circuit because of parallel connection, electric connection continues to flow in other circuits. So the light or fan……Q4 Make list of electrical appliances used in your home.A4 List of electrical appliances used in your home are tube light, fan , T.V. , radio , computer , telephone , mobile , washing machine , fridge , air cooler , A.C. , electric bulb , electric mixture , etc . L-2Q-5 STATE THE PRINCIPLE OF A LEVER STATE THE TYPES OF LEVER?A1 THE PRINCIPLE OF A LEVER IS THE PRODUCT OF THE LOAD AND THE LOAD DISTANCE IS EQUAL TO THE PRODUCT OF THE EFFORT AND THE EFFORT DISTANCE. THERE ARE THREE TYPES OF LEVER 1] LEVER OF FIRST TYPE 2] LEVER OF SECOND TYPE 3] LEVER OF THIRD TYPE.6 WHAT IS A LEVER OF FIRST TYPE?A2 A LEVER IN WHICH FULCRUM IS IN BETWEEN THE LOAD AND EFFORT IS CALLED LEVER OF FIRST TYPE. EX PINCERS ,SCISSORS AND PLIERS.7 WHAT IS A LEVER OF THE SECOND TYPE? GIVE ITS THREE EXAMPLES.A3 A LEVER IN WHICH LOAD IS BETWEEN THE FULCRUM AND EFFORTIT IS CALLED LEVER OF SECOND TYPE EX NUTCRACER ,LEMON SQUEEZER, MANGO CUTTER.8 WHAT IS A LEVER OF THE THIRD TYPE? GIVE THREE EXAMPLES?

A4 A LEVER IN WHICH EFFORT IS BETWEEN THE FULCRUM AND LOAD IS CALLED LEVER OF THIRD TYPE. EX BROOM,TONGS, FISHING ROD .9 EXPLAIN WITH A DIAGRAM THAT SCISSORS IS A LEVER OF THE FIRST TYPE?A5 THE CLOTH IS CUT BY KEEPING IT BETWEEN THE TWO BLADE OF THE SCISSORS .THIS IS THE POSITION OF LOAD. FORCE IS APPLIED AT THE HANDLES OF THE BLADES AND HANDLES MOVE AT THE SCREW GIVEN AT THE MIDDLE OF THE SCISSORS .THIS SCREW IS FULCRUM SO IN SCISSORS THE FULCRUM IS BETWEEN THE LOAD AND EFFORT. SO IT IS A LEVER OF FIRST TYPE. 10 SHOW THE POSITION OF FULCRUM, LOAD AND EFFORT IN THE GIVEN FIGURES write THE TYPE OF LEVER?A6 [a]NUT CRACKER-- IN THE NUTCRACKER THE NUT IS KEPT NEAR THE FULCRUM. EFFORT IS APPLIED AT THE HANDLES SO THE LOAD IS IN BETWEEN THE FULCRUM AND EFFORT SO IT IS LEVER OF SECOND TYPE. [b] TONGS-- THE BURNING COAL IS A LOAD, THE CURVED PORTION OF THE TONGS IS THE FULCRUM AND THE EFFORT IS APPLIED IN THE MIDDLE OF THE TONGS. SO IT IS A LEVER OF THIRD TYPE.11 WRITE THE NAME OF FOUR SIMPLE MACHINE OF LEVER TYPE USED AT YOUR HOME IN THE KITCHEN?A 7 1]PINCERS-- FIRST TYPE OF LEVER. 2] TONGS-- THIRD TYPE OF LEVER. 3] LEMON SQEEZER-- SECOND TYPE OF LEVER. 4] BROOM-- THIRD TYPE OF LEVER.L-4Q12 } Take some wheat in one pan of a balance? How will you measure mass of wheat?Ans 1 Take a physical balance 2 Place the wheat in one pan 3 Put the wait of approximate mark in another pan4 If the pan containing wheat lowers down take the wheat and put the other weight of less quantity5 continue this process till both pan becomes horizontal6Mass in both the pans become equal 7 the measurement, of the weight placed in the pan is the mass of the substance.Q 13 } Which activity will you perform to find the religion between kilogram and gram?Ans 1] Take one balance put 1kg weight in one of the pan.2]Put the different weights in grams in the other pan and balance the balance.

3]The gram measurement equal to 1kg in the other pan is 1000gms.Thus 1kg =1000gmsQ 14 } Which precautions should be taken while measuring the volume of a liquid using a measuring cylinder ?Ans Precautions taken by the volume of a liquid are 1] Measuring cylinder should be kept on horizontal flat surface. 2]Upper surface of water in a measuring cylinder becomes curved.The position of the eye should be in a straight line with the lower part of curved surface.3] Find the test count of the measuring cylinder.Q15 } How will you find out least count of a measuring cylinder?Ans 1]Take a scaled measuring cylinder.2]Note the difference between two successive big marks.3]Count the number of smaller division between the two big marks.4]List count measure= measure between/number of smaller division two successive big marks =10ml/10=1ml.Thus the list between two successive count measure of the scaled measuring cylinder is 1ml.Q 16 What are the units of mass and volume? Write the formula for density and hence determine the unit of density.Ans The Unit of mass are milligram, gram, kilogram, quintal, ton. The unit of volume are cubiccm or cubicm. Density=mass/volUnit of density are gm/cm3 or kg/m3.L-5Q17 Explain the following terminology:1) Angle of incidence. 2) Angle of reflection.Ans.1) Angle of incidence:-The angle between the normal and incident ray is called angle of incidence. 2) Angle of reflection:- The angle between the normal and reflected ray is called angle of reflection. Q 18 . State the laws of reflection of light?Ans. The laws of reflection of light:- 1) Measures of angle of incidence and angle of reflection are equal.2) The incident ray and reflected ray lie on opposite sides of normal.3) The incident ray, reflected ray and the normal are in the same plane. 19 . Explain with the diagram, the regular reflection of light?Ans. Parallel rays incident on polished surface gets reflected parallally. Such reflection is known as uniform reflection or regular reflection.Q 20 . State the characteristics of the image formed by a plane mirror?Ans. 1. The images of the same size 2. The image is virtual and erect.3. The image is perverted ( laterally inverted )

4. Object and image are equidistant from the mirror.Q 21 . Which English capital letters of the alphabet read the same in the plane mirror?Ans. The English capital letters of the alphabet are read the same in the plane mirror are X, A, B, V, H, I etc.Q22 . Why are the different designs form in a kaleidoscope?Ans. The rectangular strips of the plane mirror are arranged at 60° with each other. Five images and the original object which makes a total of six similar images are seen in the two mirrors such images are formed of all various pieces so a numbered of colored geometric shaped are formed.Q23 . Calculate the number of images formed by placing an object between two plane mirrors, when the angle between them is 45°?Ans. No. of images= 360° -1 Angle between two plane mirrors = 360° -1 45° = 7 images are formedQ24. Which activity will you performed to explain the phenomenon of reflection of light?Ans. (1) Take a small plane mirror. (2) Allow the torch light to fall on it. (3) Now adjust the incident torch light and try to see its reflection on the wall or screen. (4) A bright spot of light is seen on the wall. (5) Here, ray of light incident of mirror is reflected by the mirror which we see on the wall as a bright spot.Q 25 . Observe the image in a plane mirror. How will you explain lateral inversion?Ans. When we lift our right hand, the left hand of our image raises. When we lift our left hand the right hand of our image is raised. Thus, this ray the images show lateral images.L-7 26 . Give general information regarding atom. Ans: 1) . Atom is the basic unit of an element.2) . It consists of three particles: Protons, Neutrons and electrons.3) . Protons have positive charge, Neutrons have no charge and electrons have negative charge.4). The positive centre of an atom is called nucleus.5) Nucleus consists of protons and neutrons.6) Electrons move around the nucleus in a definite circular path called orbit.

7). In an atom the number of protons and electrons are same so it is neutral.8). Mass of protons and neutrons is nearly same.27 State two properties of a compound.Ans: Properties of a compound are: 1. Constituent elements are in fixed proportion.2. Constituent elements lose their property.28 State properties of a mixture.Ans: Properties of a mixture are: 1 Constituent elements are not in fixed proportion.2. Constituent elements retain their property.29 . Explain that water is a compound.Ans: Water is a compound because water is formed when hydrogen and oxygen are mixed in a fixed proportion. Hydrogen and oxygen lose their property. Hydrogen is combustible; oxygen supports combustion while water formed is neither combustible nor supports combustion.L-No 8 30 State two functions of the skeleton?Ans Two functions of skeleton are 1 it gives shape and support to the body .2 It gives strength to the body 3 it protects the delicate internal organs of our body.31 What are joints? State two types of joints?Ans The place where two bones meet in the skeleton is called joints. The two types of joints are 1 immovable joints 2movable joints.32 Where do we have joints in our body?Ans We have joints in our body in hands, legs , skull, rib cage and vertebral column .33 Where are the flexible joints found in our body?Ans The flexible joints found in our body are 1 joints of vertebrae 2 joints of fingures 3 joints of shoulders 4 joits bones of elbow 5 knee joints34 Where are inflexible joints found in our body?Ans In flexible joints found in our body are 1 bones of cheek 2 bones of ribs 3 Bones of skull 4 Bones of nose 6 Bones of pelvic Girdle .35 what would happen , if there are no bones in our body?Ans if there are no bones in our body, our body would not havethe definite shape or size.36 What is a muscle? State two types of muscles with examples ?Ans muscles is a group of tissues in the body that can contract and relax and perform movements of organs in the body. The types of muscles are 1 voluntary

muscle eg- muscles of neck , hands and legs 2 Involuntary muscles eg- muscles of lungs, heart and intestine.37 State two functions of muscular system Ans Two functions of muscular system are 1 due to their elastic nature muscles help in locomotion and movement 2 Muscles give shape to the body 3 Air enters into the lungs with the help of muscles 4 muscles push the food in alimentary canal through food pipe.38 Write in short about pectoral girdle and pelvic girdleAns pectoral girdle- it is made up of 4 bones . it is connected with chest bone on the ventral side and with the vertebral column by muscles on dorsal side. Pectoral girdle helps the shoulders fro lurching Pelvic girdle- It forms the base of pelvic region and hip . it is connected to the vertebral column on the backside and joint together in front . hip bones are connected the hind limbs on both lateral sides . there are two bones in pelvic girdle . L-939 ) The hot water taken for a bath becomes cold after sometime. Why does this happen?Ans: The hot water taken for a bath becomes cold after sometime because it loses heat to the surrounding. The temperature of hot water is more than the surroundings. After sometime the hot water becomes cold. 40 ) Why do we blow out over tea while drinking hot tea?Ans: We blow out over tea while drinking hot tea so that the tea loses heat and cools faster.41) Why is mercury filled in a thermometer?Ans: Mercury is a metal in liquid state. It is expanded when heat is supplied to it. It never sticks with the tube, so it can easily move in glass tube. Because of glittering of mercury, the thermometer can be seen easily. So the temperature of the substances can be easily read. 42 Which precautions should be taken while measuring the body temperature with a clinical thermometer?Ans: The following precautions should be taken while measuring the body temperature with a clinical thermometer:1. It should be washed properly.2. It should be given a light jerk to bring the mercury level to the lowest mark.3. The bulb should be kept in contact of the patient’s body for a minute.4. Temperature should be noted by keeping the eye horizontal with the level of mercury in the thermometer.43) Why is a light jerk given to the clinical thermometer before using it?

Ans: There is construction in the capillary tube near the bulb. So the mercury level remains steady at the temperature measured before. So to bring back mercury to the lowest mark it is jerked so that we can get correct reading. 44 What happens, if there is no constriction in the capillary tube in a clinical thermometer? Ans: If there is no constriction in the capillary tube in a clinical thermometer the mercury level will fall down as soon as the thermometer is removed from the contact of the body and correct reading cannot be obtained. Due to construction the mercury level does not fall even after it is removed from the contact of the patient’s body. 45) Take a cup and a bowl. Fill water in them. Put both of them in a refrigerator. In which vessel will the water become cool quickly? Why?Ans: Water in cup will cool faster because it has less mass water in bowl has more mass so it will cool slowly . 46) Fill a cup of glass with hot water. Fill the pan with cold water. Place the cup in the pan. Touch the water in the pan after sometime. Note your observation. Explain thermal equilibrium based on your observation.Ans: The water in the pan has become slightly warm whereas the water in the glass has become slightly cool. The heat transfers from hotter substance to colder substance due to temperature difference.L – No 10 47 How does automobiles and industries spread pollution in the atmosphere?Ans 1 Smoke Exhausted by scooters, trucks , motorcars spread pollution in air.2 Upper layer of air gets polluted because of poisonous gases produced from the fuels of jetplanes , rockets , missiles .3 industries use chemical substances and so carbon particles, poisonous gases like carbon monoxide , sulphur dioxide and hydrogen sulphide are produced and mix with the air and pollute it.4 wood and coal are used in many industries which produces carbon dioxide and carbon monoxide which spread air pollution.48 why do we feel suffocation in the closed hall where many people gather?Ans We feel suffocation in the closed hall where many people gather because people exhale carbon dioxide and so the proportion of carbon dioxide increases moreover there is no entry of fresh air in the closed hall so we feel suffocation due to pollution.49 Why do doctors and nurses cover their mouths with masks?Ans Doctors and nurses cover their mouths with masks so that the entry of micro organisms can be avoided and we may not suffer from infections disease .50 Why is PUC of automobiles required?

Ans PUC means Pollution Under Control . PUC certificate is given to vehicles owners , to check the combustion of fuel and level of pollutants being emitted from the exhaust of their vehicles . So to reduce pollution of air PUC of automobiles is required. 51 What care should be taken of automobiles to reduce pollution?Ans {1} Proper arrangement should be made for discharge of smoke from industries .{2} Engine of the vehicles should be checked at regular intervals and should be serviced at proper intervals. {3} PUC of vehicles should be made . {4} Fuels and engine oils without any adulteration should be used. {5} Fuels producing less pollution should be used in vehicles. {6} The rules regarding pollution control should be strictly followed.52 How do the trees help us to control air pollution?ANS 1Trees absorb carbondioxide (CO2)and releases oxygen (o2) during the process of photosynthesis . It reduces air pollution. 2 Plants release moisture through transpiration.53 State the effects of air pollution on human beings Ans the effects of air pollution on human beings are [1]Irritation in eyes ,nose and throat.[2]Sneezing [3] Difficulty in breathing [4] Cancer of trachea and lungs [5] Infertility , diseases of skin and eyes.54 State the natural factors that reduce air pollution .Ans the natural factors that reduce air pollution are plant, rain wind sunlight.55 Explain green house effect?Ans Carbon dioxide possesses the property to absorb heat .When solar radiation enters our atmosphere , our soil absorbs some radiation is reflected back but that is absorbed by atmosphere carbondioxide . thus it maintains the atmospheric temperature . But due to increased Co2 temperature of our earth is also increased . This effect in known as Greenhouse effect.56 What is acid rain?ans when the moisture in the atmosphere increases the proportion of dry particles and acidic gases like sulphur dioxide and nitrogen oxide etc dissolve in the moisture and produce sulphuric acid H2SO4 and nitric acid HNO3 respectively , it falls in the land with the rain and it is called acid rain.57 State the effects of acid rain?Ans The effects of acid rain are 1 deforestation 2 Decrease in the soil nutrients and land becomes barren 3 Big monumental buildings gets damage.L-1158) .Which members are included in the solar system?

A. Members included in the solar system are sun ,planets ,satellites ,asteroids ,comets ,and meteors. 59) .What is a solar system? Write the names of planet of the solar system?A .The sun and the planets moving around the sun is called the solar system. Planets of solar system are Mercury, Venus ,Earth ,Mars ,Jupiter ,Saturn ,Uranus and Neptune.60) .What are interior planets? Name them ?A .The planets whose orbits are smaller than the orbit of the Earth are called interior planets . Mercury and Venus are interior planets.61) .What are outer planets ? Name them ?A. The planets whose orbits are bigger than the orbit of Earth are called outer planets. Mars ,Jupiter ,Saturn ,Uranus and Neptune.62) .Write four special features each of mercury and venus?A. Mercury:-1)It is the nearest to the sun . 2) It has no atmosphere .3) It has no satellite .4) Life does not exist there .5) Days and nights are longer.Venus:-1)It is the nearest planet to the earth .2) It is the brightest planet. 3) It has no satellite. 4) It is seen in east before sunrise and in the west after sunset.5) It is known as the morning star.6) It has atmosphere.63) . Write four special features each of Mars and Jupiter? A. Mars:- 1) It is the red planet.2) Its atmosphere is like earth but less dense.3) It has satellites.4) There is a vast difference in the temperature of day and night.Jupiter - 1) It is the largest planet .2) It is 1317 times bigger than the Earth .3) It has highest gravitational force .4) Its diameter is 11 times more than that of the Earth .64 ) . Write a short note on asteroids.A. 1)They are members of solar family.2)They are small rocks which failed to become the planet during the formation of solar system.3)They are found between the orbits of Mars and Jupiter.4)They revolve around the sun.5)They are more in number.

65 . Give four reasons for the danger of existence of tigerAns: The reasons for the danger of existence of tiger are:1} Hunted by humans.2} Human sells skin, claws and other organs for earning money.3} Due to deforestation tiger lose their habitat.4} Tigers do not get food due to the decreasing number of herbivores.5} Due to air pollution and noise pollution.66. What can be done to protect and nurture endangered animals?Ans: The following steps can be taken to protect endangered animals:1} Stop deforestation and grow more trees.2} Protect air, water and soil pollution.3} Use chemical fertilizers and pesticides carefully.4} Stop hunting of birds and animals.5} By developing national parks and sanctuaries we should nurture environment by protecting useful birds, animals and insects.67. When does the environment equilibrium gets disturbed? What type of problems arise due to environmental imbalance?

The environmental equilibrium gets disturbed by:1} Cutting of trees.2} Industrialization.3} Pollution of air, water, soil.4} Noise pollution.5} Use of chemical fertilizers and pesticides.

Problems due to environmental imbalance:1} Problems like Heavy rain, Draught, Extreme heat, Earthquake, Tsunami, Global Warming, etc.2} Extinction of birds and animals.

68. Which type of efforts would you do to conserve the environmental equilibrium?Ans: The following steps should be taken to conserve the environmental equilibrium:1} Grow more trees.2} Stop deforestation.3} Protect air, water and soil against pollution.4} Should destroy harmful waste properly.5} By protecting useful insects, birds and animals.69. Give reasons for the endangered or threatened bird species.Ans: The reasons for the endangering and threatening bird species are:

1} Loss of Habitat.2} Scarcity of food due to cutting of trees.3} They migrate due to noise pollution, scarcity of water bodies and lost of natural habitat.4} Their health is lost due to industrialization as well as water, air, soil pollution.5} By eating toxic {poisonous} food due to use of pesticides and chemical fertilizers used by farmers.Q- 7 Difference Between

1)Electrical Conductor and Electrical Insulators

Electrical conductor1) The substance through which an electric current can pass is called Electrical Conductor .2) Eg. Iron , Copper , Aluminum

Electrical insulators 1) The substance through which an electric current cannot pass is called Electrical Insulator 2) Eg. Plastic , wool , match stick

L-22) Lever of First Type and Lever of Second Type LEVER OF THE FIRST TYPE 1 .IN THIS TYPE OF LEVER THE FULCRUM IS BETWEEN THE LOAD AND THE EFFORT. 2. IN THIS TYPE THE EFFORT DISTANCE MAY BE LESS MORE OR EQUAL TO LOAD.3) Eg. Scissors , pincers

LEVER OF THE SECOND TYPE1. IN THIS TYPE OF LEVER THE LOAD IS BETWEEN THE FULCRUM AND EFFORT.2. IN THIS TYPE THE EFFORT DISTANCE IS ALWAYS MORE THEN THE LOAD DISTANCE.3 Eg Nutcracker , lemon squeezer

LEVER OF THE SECOND TYPE1. IN THIS TYPE OF LEVER THE LOAD IS BETWEEN THE FULCRUM AND EFFORT.2. IN THIS TYPE THE EFFORT DISTANCE IS ALWAYS MORE THEN THE LOAD DISTANCE.

3 Eg Nutcracker , lemon squeezer .

LEVER OF THE THIRD TYPE1 IN THIS TYPE OF LEVER THE EFFORT IS IN THE BETWEEN THE EFFORT AND LOAD.

2 IN THIS TYPE THE EFFORT DISTANCE IS ALWAYS LESS THAN THE LOAD DISTANCE.

3) Eg . Broom , fishing hook , coal tongs

L-44) Mass and Weight Mass Weight1] The quantity of materialin a given substance is called mass.

1] The gravitational force on the earth acting on a body is called its weight

2] Mass is measured by simple balance. 2] Weight is measured by spring balance.

3] Unit of mass: gram, milligram, kilogram.

3] Unit of weight: newton, dyne.

L-55) Regular Reflection and Irregular Reflection Regular reflection

1. Flat, even and smooth surface is required for regular reflection.2. The incident ray get reflected parallely.3. Reflected rays move back in the same direction.

Irregular reflection1. Rough and uneven surface is required for irregular reflection.2. The incident ray does not get reflected parellally.3. Reflected rays move back in the different direction.

6) Element and Compound

Element

Compound1) Its unit is an atom. 1) Its unit is a molecule.

2) It is denoted by symbol. 2) It is denoted by formula.

7) Compound and Mixture

Compound Mixture

1) More than one element combined in definite proportion to form a new substance with different properties. It is compound.

1) More than one element or compound mix in any proportion in such a way that they retain their property to form a mixture.

2) Constituent elements are in fixed proportion.

2) Constituent elements are not in fixed proportion.

3) Constituent elements lose their property.

3) Constituent elements retain their property.

4) Eg: Water, Salt. 4) Eg: Air, Soil.

EX-8 Experiment1 Describe with a neat diagram , an experiment to find the volume of a stone using a measuring cylinderApparatus and materials –Measuring cylinder, stone, water, strong threadFigure-Procedure- 1 Take a irregular shaped stone 2 Tie it with thin strong string 3 Take a measuring glass. 4 Fill it half with water. 5 Place it on horizontal flat surface. 6 Note the level of water (V)1

7 Immerse the stone tred with string in the measuring glass slowly and observe the level of water (V2)Observation- The level of water rises V1 =60 ml V2 = 70 ml.

Calculation-Volume of stone – v1-V2

=70-60 ml =10ml1ml = 10 cubic cm Therefore 10 ml=100 cubic cmConclusion: Thus the volume of irregular stone is 10 cubic cm.

2 Describe, with a neat diagram, an experiment to find the volume stone using a displacement vessel.Aim- To find the volume stone using a displacement vessel.Apparatus and materials- A displacement vessel, stone, water, measuring cylinder, strong string.Figure-Procedure-1 Take irregular shape stone. 2 Tie it with string. 3 Take a displacement vessel. 4 Place it on a horizontal flat surface. 5 Fill it with water and allow the access water to flow. 6 Adjust the measuring cylinder near the end of the nozzle. 7 Slowly immerse the stone tied with tread completely in the water. 8 Collect the displace water in the measuring cylinder. 9 Note down the water collected in the measuring cylinder.Observation- The volume of water displaced by the stone and collected in the measuring cylinder is 20 ml.Conclusion- volume of displaced water = volume of stone =20 ml = 20 cubic cm 3 Describe an experiment, with diagram, to prove the laws of reflection of light.Aim- To prove the laws of reflection of light.Apparatus and materials- Plane mirror, mirror stand, cardsheet, sketch pen, laser torch, compass box.Figure-Procedure- 1 Arrange the plane mirror vertically on the stand placed on card-sheet. 2 Mark the reflecting surface mm’. 3 Throw light on mirror so that it touches the reflecting surface as shown in the figure. 4 Mark points A and X on the path of incident ray. 5 The ray touches at point O. 6 Mark point Y and B on the path generated by reflected ray of laser. 7 Remove the plane mirror and draw line NO mm’. 8 Measure Li and Lr. 9 Observe the direction of incident ray and the reflected ray with reference to normal.Observation - 1) Angle AON = Angle BON 2) Ray AO and Ray OB are on opposite side 3) Ray OA , OB , and On are in same place .Conclusion – The laws of reflection are concluded by this experiment .