[Maximum number: 2]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 2]

The diagram below shows part of a downhill ski course which starts at point $\mathrm{A}, 50 \mathrm{~m}$ above level ground. Point B is 20 m above level ground.

(a)

A skier of mass 65 kg starts from rest at point A and during the ski course some of the gravitational potential energy transferred to kinetic energy.

[ 2 ]

(i)

Some of the gravitational potential energy transferred into internal energy of the skis, slightly increasing their temperature. Distinguish between internal energy and temperature.

[ 2 ]

[Maximum number: 1]

In an experiment, data were collected on the variation of specific heat capacity of water with temperature. The graph of the plotted data is shown.

(a)

The uncertainty in the values for specific heat capacity is 5 %.

Water of mass $(100 \pm 2) \mathrm{g}$ is heated from $(75.0 \pm 0.5)^{\circ} \mathrm{C}$ to $(85.0 \pm 0.5)^{\circ} \mathrm{C}$ .

[ 1 ]

(i)

Calculate the energy required to raise the temperature of the water from $75^{\circ} \mathrm{C}$ to $85^{\circ} \mathrm{C}$ .

[ 1 ]

[Maximum number: 4]

A thermometer and an electrical heater are inserted into small holes in a solid aluminium block.

The heater is turned on at time t=0. The graph shows the variation of the temperature $\theta$ of the block with time t.

(a)

Suggest why the temperature of the block approaches a constant value.

[ 2 ]

(b)

The power of the heater is 52 W . The mass of the block is 0.85 kg . Determine the specific heat capacity of aluminium.

[ 2 ]

[Maximum number: 2]

A group of students is trying to determine the density and the viscosity of a liquid.

To determine the density, they use a balance to read the mass m of a sphere in air and immersed in the liquid.

They use a sphere of volume $V=1.827 \times 10^{-7} \mathrm{~m}^{3}$ .
The readings are $m_{\text {air }}=1.427 \mathrm{~g}$ in air and $m_{\text {lmmersed }}=1.208 \mathrm{~g}$ in the liquid.
The readings are different due to buoyancy. The buoyancy force $F_{\mathrm{b}}$ is given by

F_{\mathrm{b}}=\rho V g

where V is the volume of the sphere and $\rho$ is the density of the liquid.

(a)

Calculate the density of the liquid.

[ 2 ]

[Maximum number: 7]

This question is about energy.

At its melting temperature, molten zinc is poured into an iron mould. The molten zinc becomes a solid without changing temperature.

(a)

Outline why a given mass of molten zinc has a greater internal energy than the same mass of solid zinc at the same temperature.

[ 3 ]

(b)

The zinc is allowed to cool in the mould. The temperature of the iron mould was $20^{\circ} \mathrm{C}$ before the molten zinc, at its melting temperature, was poured into it. The final temperature of the iron mould and the solidified zinc is $89^{\circ} \mathrm{C}$ .

The following data are available.

Using the data, determine the specific heat capacity of zinc.

[ 4 ]

[Maximum number: 1]

Insulated solid copper rods of different diameters and fixed length are placed in thermal contact with two objects X and Y , maintained at different temperatures $T_{X}$ and $T_{Y}$ respectively. The diagram shows the setup with one such rod.

Which graph shows the variation with rod diameter d of the rate of thermal energy transfer $\frac{\Delta Q}{\Delta t}$ along the rod?

A

B

C

D

[Maximum number: 1]

X and Y are two spherical black-body radiators. X has a radius R and emits half the total power of Y . The absolute temperature of X is double that of Y .

What is the radius of Y?

A

$2 \sqrt{2} R$

B

4 R

C

$4 \sqrt{2} R$

D

16 R

(a)

Describe the mechanism of heat transfer by conduction.

The diagram shows a wall separating the inside of a room from the outside. The temperature of the room is kept constant by a heater.

The following data are available:

\begin{aligned} \text { Thickness of wall } & =0.25 \mathrm{~m} \\ \text { Area of wall } & =18 \mathrm{~m}^{2} \\ \text { Thermal conductivity of wall } & =1.3 \mathrm{Wm}^{-1} \mathrm{~K}^{-1} \\ \text { Constant room temperature } & =22^{\circ} \mathrm{C} \\ \text { Constant outside temperature } & =13^{\circ} \mathrm{C} \end{aligned}

[ 2 ]

(b)

Estimate the rate at which thermal energy leaves the room through the wall giving the answer with an appropriate unit.

[ 2 ]

(c)

At night the outside temperature falls below $13^{\circ} \mathrm{C}$ . The heater is turned off at time t=0. The graph shows the variation with time t of the temperature T of the room.

[ 1 ]

(i)

Outline why the magnitude of the gradient of the graph decreases.

[ 1 ]

[Maximum number: 1]

Two blocks P and Q of the same mass are placed in thermal contact with each other until they reach thermal equilibrium. In reaching thermal equilibrium the temperature of P increases by 10 K , and the temperature of Q decreases by 20 K . Thermal energy exchange with the surroundings is negligible.

Which statement is correct?

A

P has a greater specific heat capacity than Q.

B

Q has a greater specific heat capacity than P.

C

The magnitude of the change in internal energy is greater for P than for Q.

D

The magnitude of the change in internal energy is greater for Q than for P.

Question 1

Question 1(d)

Question 1

Question 1(a)

Question 1(a)(ii)

Question 1

Question 1(c)

Question 1(c)(i)

Question 1

Question 1(b)

Question 1(d)

Question 1

Question 1(c)

Question 2

Question 2(a)

Question 2(b)

Question 6

Question 6

Question 2

Question 2(a)

Question 2(b)

Question 2(c)

Question 2(c)(i)

Question 7