The radius of coil of a Tangent galvanometer which has 10 ...€¦ · Contact info : 8400-582-582, 8604-582-582 Question No. : 01 The radius of coil of a Tangent galvanometer which

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Question No. : 01

The radius of coil of a Tangent galvanometer which has

10 fturns is 0.1m. The current required to produce a

deflection 60° (BH = 4×10–5T) is

(A) 3A

(B) 1.1A

(C) 2.1A

(D) 1.5A


Question No. : 02

Two identical bar magnets are placed one above the other such

that they are mutually perpendicular and bisect each other. The

time period of this combination in a horizontal magnetic field is T.

The time period of each magnet in the same field is;

(a) (b)

(c) (d)

2 T1

42 T

1

42 T

1

22 T


Question No. : 03

The length of a magnet is large compared to its width and

breadth. The time period of its oscillation in a vibration

magnetometer is 2 s. The magnet is cut along its length into

three equal parts and three parts arre then placed on each

other with their like poles together. The time period of this

combination will be;

(a) 2 s (b) 2/3 s

(c) s (d) s2 3 2/ 3


Question No. : 04

Two magnets are held together in a vibration magnetometer and

are allowed to oscillate in the earth’s magnetic field. With like

poles together, 12 oscillations per minute are made but for unlike

poles together only 4 oscillations per minute are executed. The

ratio of their moments is;

(a) 3 : 1

(b) 1 : 3

(c) 3 : 5

(d) 5 : 4


Question No. : 05

A bar magnet has a magnetic moment equal to

It is suspended in a magnetic field which has a

magnetic induction (B) equal to The magnet

vibrates with a period of vibration equal to 15 sec. The moment of

inertia of the magnet is;

(a) (b)

(c) (d)

55 10 weber m.

48 10 tesla.

222.5kg m 211.25kg m

25.62kg m7 27.16 10 Kg m


Question No. : 06

The time period of a freely suspended magnet is 4 seconds.

If it is broken in lengtth into two equal parts and one part

is suspended in the same way, then its time period will be;

(a) 4 sec

(b) 2 sec

(c) 0.5 sec

(d) 0.25 sec


Question No. : 07

The sensitivity of a tangent galvanometer is increased

if;

(a) Number of turn decreases

(b) Number of turn increases

(c) Field increases

(d) None of the above


Question No. : 08

Two tangent galvanometers having coils of the same radius

are connected in series. A current flowing in them produces

deflections of 60° and 45° respectively. The ratio of the

number of turns in the coils is

(A) 4/3 (B)

(C) (D)

( 3 1) /1

( 3 1) /( 3 1) 3 /1


Question No. : 09

Relative permittivity and permeability of a material are

er and mr respectively. Which of the following values of

these quantities are allowed for a diamagnetic material;

(a) (b)

(c) (d)

r r1.5, 0.5e m r r0.5, 0.5e m

r r1.5, 1.5e m r r0.5, 1.5e m


Question No. : 10

If a diamagnetic substance is brought near north or south

pole of a bar magnet, it is

(A) Attracted by the poles

(B) Repelled by the poles

(C) Replelled by the north pole and attracted by the south

pole

(D) Attracted by the north pole and repelled by the south

pole


Question No. : 11

A paramagnetic substance of susceptibility 3 × 10-4 is

placed in a magnetic field of 4 × 10-4. Then the intensity

of magnetization in the units of Am–1 is;

(a) (b)

(c) (d)

81.33 10 80.75 10

812 10 814 10


Question No. : 12

Choose the correct statement;

(a) A paramagnetic material tends to move from a strong

magnetic field to weak magnetic field

(b) A magnetic material is in the paramagnetic phase below

its Curie temperature

(c) The resultant magnetic moment in an atom of a

diamagnetic substance is zero

(d) Typical domain size of a ferromagnetic material is 1 nm


Question No. : 13

Relative permeability of iron is 5500, then its magnetic

susceptivity will be;

(a) (b)

(c) 5501 (d) 5499

75500 10 75500 10


Question No. : 14

Which of the following is true;

(a) Diamagnetism is temperature dependent

(b) Paramagnetism is temperature dependent

(c) Paramagnetic is temperature independent

(d) None of these


Question No. : 15

If the angular momentum of an electron is then the

magnitude of the magnetic moment will be;

(a) (b)

(c) eJ 2m (d)

eJ

m

eJ

2m

2m

eJ


Question No. : 16

Which of the following statements is incorrect about

hysteresis;

(a) This effect is common to all ferromagnetic substances

(b) The hyteresis loop area is proportional to the thermal

energy developed per unit volume of the material

(c) The hysteresis loop area is independent of the thermal

energy developed per unit volume of the material

(d) The shape of the hysteresis loop is characteristic of the

material


Question No. : 17

A small rod of bismuth is suspended freely between the

poles of a strong electromagnet. It is found to arrange

itself at right angles to the magnetic field. This

observation establishes that bismuth is;

(a) Diamagnetic (b) Paramagnetic

(c) Ferri-magnetic (d) Antoferro-magnetic


Question No. : 18

Among the following properties describing diamagnetism identify

the property that is wrongly state;

(a) Diamagnetic materials do not have permanent magnetic

moment

(b) Diamagnetism is explained in terms of electromagnetic

induction

(c) Diamagnetic materials have a small positive susceptibility

(d) The magnetic moment of individual electrons neutralize each

other


Question No. : 19

Needles N1, N2 and N3 are made of ferromagnetic, a

paramagnetic and diamagnetic substance respectively. A

magnet when brought close to them will;

(a) Attract N1 strongly, N2 weakly and repel N3 weakly

(b) Attract N1 strongly, but repel N2 and N3 weakly

(c) Attract all three of them

(d) Attract N1 and N2 strongly but repel N3


Question No. : 20

The magnetic susceptibility of a paramagnetic

substance at –73°C is 0.0060 , then its value at –173°C

will be

(A) 0.0030

(B) 0.0120

(C) 0.0180

(D) 0.0045

Question No. : 21

Two identical short bar magnets, each having magnetic moment

M, are placed a distance of 2d apart with axes perpendicular to

each other in a horizontal plane. The magnetic induction at a

point midway between them is;

(a) (b)

(c) (d)

0

3

M( 2)

4 d

m

0

3

M( 3)

4 d

m

0

3

2 M

d

m

0

3

M( 5)

4 d

m


Question No. : 22

The true value of angle of dip at a place is 60o, the

apparent dip in a plane inclined at an angle of 30o with

magnetic meridian is;

(a) (b)

(c) (d) None of these

1 1tan

2

1 2tan

3

1tan 2


Question No. : 23

A vibration magnetometer consists of two identical bar

magnets placed one over the other such that they are

perpendicular and bisect each other. The time period of

oscillation in a horizontal magnetic field is 25/4 seconds. One of

the magnets is removed and if the other magnet oscillates in

the same field, then the time period in seconds is;

(a) 21/4 (b) 21/2

(c) 2 (d) 23/4


Question No. : 24

A solenoid has a core of a material with relative permeability

500 and its windings carry a current of 1A. The number of

turns of the solenoid is 500 per metre. The magnetization of

the material is nearly;

(a) (b)

(c) (d)

3 12.5 10 Am5 12.5 10 Am

3 12.0 10 Am 5 12.0 10 Am


Question No. : 25

A thin diamagnetic rod is placed vertically between the poles of an

electromagnetic. When the current in the electromagnet us

switched on, then the diamagnetic rod is pushed up, out of the

horizontal magnetic field. Hence the rod gains gravitational

potential energy. The work required to do this comes from;

(a) The current source

(b) The magnetic field

(c) The lattice structure of the material of the rod

(d) The induced electric field due to the changing magnetic field


Question No. : 26

A bar magnet is demagnetized by inserting it inside a

solenoid of length 0.2m, 100 turns, and carrying a

current of 5.2 A. The coercivity of the bar magneti is

(A) 1200A/m

(B) 2600A/m

(C) 520A/m

(D) 285A/m


Question No. : 27

At some location on earth the horizontal component of earth’s

magnetic field is 18×10–6T. At this location, magnetic needle of

length 0.12m and pole strength 1.8Am is suspended from its

mid-point using a thread, it makes 45° angle with horizontal

in equilibrium. To keep this needle horizontal, The vertical

force that should be applied at one of its ends is

(A) 3.6×10–5N (B) 6.5×10–5N

(C) 1.3×10–5N (D) 1.8×10–5N


Question No. : 28

A paramagnetic substance in the form of a cube with

sides 1 cm has a magnetic dipole moment of 20×10–6J/T

when a magnetic intensity of 60×103A/m is applied. Its

magnetic susceptibility i

(A) 2.3×10–2

(B) 3.3×10–2

(C) 3.3×10–4

(D) 4.3×10–2


Question No. : 29

A paramgnetic meterial has 1028 atom/m3. Its magnetic

susceptibility at temperature 350K is 2.5×10–4. Its

susceptibility at 300 K is

(A) 3.672×10–4

(B) 3.626×10–4

(C) 3.276×10–4

(D) 2.672×10–4


Question No. : 30

A magnetic compass needle oscillates 30 times per minute

at a place where the dip is 45°, and 40 times per minute

where the dip 30°. If B1 and B2 are are respectively the

total magnetic field due to the earth at the two places,

then the ratio B1/B2 is best given by

(A) 2.2 (B) 1.8

(C) 0.7 (D) 3.6

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The radius of coil of a Tangent galvanometer which has 10 ...€¦ · Contact info : 8400-582-582, 8604-582-582 Question No. : 01 The radius of coil of a Tangent galvanometer which