Name: Class: Date:

SMK (L) Methodist Kuala LumpurPhysics Form 4

REINFORCEMENT CHAPTER 4 - HEAT

Section A1. Diagram shows a mercury-in-glass thermometer. The distance between the 0oC and the 100oC markings

is 25 cm.

At which temperature is the end of the mercury thread 15 cm from the 0oC?A 50oC B 60oC C 62oC D 72oC

2. Diagram shows a thermometer.

Which design features will increase the sensitivity of this thermometer?Bulb Capillary tube

A Thin glass NarrowB Thin glass WideC Thick glass NarrowD Thick glass Wide

3. Diagram shows an alloy in the water. The energy given off as heat by 300 g of the alloy as it cools through 50oC raises the temperature of 300 g of water from 30oC to 40oC. The specific heat of water is 4200 J kg-1 oC-1.

What is the specific heat of the alloy in J kg-1 oC-1?A 840 B 1050 C 1400 D 2520

4. Why do people feel cool if they do not dry themselves after swimming in the sea?A Water is evaporated and causes cooling.B Water insulates them from the warm water.C Water is a good conductor of heat.D Water is cooler than the air.

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5. The air pressure in a car tyre is 200 kPa at a temperature of 25oC. What is the air pressure in the tyre at a temperature of 37oC?A 192 kPa B 296 kPa C 190 kPa D 208 kPa

6. Diagram shows a metal cylinder of mass 5.0 kg and specific heat capacity 400 J kg-1 oC-1.

What is the temperature rise of the cylinder 10 seconds after the heater is switched on?A 0.20oC B 0.80oC C 1.25oC D 5.00oC

7. Which graph shows the relationship between the volume and absolute temperature of a fixed mass of gas at constant pressure?

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Section B1. Diagram shows a pressure cooker for cooking food at high temperature.

(a) What is meant by pressure? [1 mark]

(b) i. Explain why the gas pressure increases with the increase of the temperature. [2 marks]

ii. Based on the answer in 1(b)i, state the gas law involved. [1 mark]

iii. State the effect of high gas pressure on the boiling point. [1 mark]

(c) The air pressure of the pressure cooker is 1 × 105 Pa, at the temperature of 27oC. What is the temperature of the air, when the air pressure is 1.5 × 105 Pa? [2 marks]

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2. Diagram shows an arrangement to investigate the relationship between pressure and volume of a fixed mass of gas at constant temperature. The pressure of the air in the glass tube is measured by a pressure gauge and the pressure can be increased by using the bicycle pump. The pump of the gas is 1.5 × 105 Pa when the volume is 80 cm3.

(a) Explain how a gas exerts a pressure on the walls of its container. [1 mark]

(b) State Boyle’s law. [1 mark]

(c) Find the volume of the gas when pressure is 2.5 × 105 Pa. [2 marks]

(d) Find the pressure of the gas when the volume is 60 cm3. [2 marks]

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