CAIE A-Level Physics 14.1.1 Direction of Thermal Energy Transfer

Practise explaining that thermal energy transfers from a region of higher temperature to a region of lower temperature until thermal equilibrium is approached.

[Maximum number: 4]

Use the information in (i) to draw, on Fig. 1.1, a line to represent the temperature of the block, assuming no energy losses to the surroundings.

(a)

State

[ 1 ]

(i)

what may be deduced from the difference in the temperatures of two objects,

[ 1 ]

(b)

A block of aluminium of mass 670 g is heated at a constant rate of 95 W for 6.0 minutes. The specific heat capacity of aluminium is $910 \mathrm{Jkg}^{-1} \mathrm{~K}^{-1}$ . The initial temperature of the block is $24^{\circ} \mathrm{C}$ .

[ 3 ]

(i)

In practice, there are energy losses to the surroundings. The actual variation with time t of the temperature $\theta$ of the block is shown in Fig. 1.1.

Fig. 1.1

[ 3 ]

1. sketch: straight line from (0,24) to (6,80)

2. temperature drop due to energy loss $=(80-64)=16^{\circ} \mathrm{C}$

energy loss $=0.670 \times 910 \times(80-64)=9800\,\mathrm{J}$

or

energy to raise temperature to $64^{\circ} \mathrm{C}=0.670 \times 910 \times(64-24)$ $=24400\,\mathrm{J}$ $\text{loss}=(95 \times 6 \times 60)-24400=9800\,\mathrm{J}$

All question bank results loaded

14.1.1—(thermal) energy is transferred from a region of higher temperature to a question 1

Question (a)

Question (i)

Question (b)

Question (i)