Physics 9702 · AS & A Level · Specific heat capacity and specific latent heat

Specific heat capacity and specific latent heat — practice question

(a)[2]

Define what is meant by specific latent heat.

(b)

An electrical heater is placed in some ice that is melting and is held in a funnel, as shown in Fig. 3.1. The heater is switched on and, once the ice is melting at a steady rate, the mass $m$ of ice melted in $5.0$ minutes is measured, together with the power $P$ of the heater. The power $P$ of the heater is then raised. A second reading of the mass $m$ of ice melted in $5.0$ minutes is taken when the ice is again melting at a steady rate. The values of $P$ and $m$ are given in Fig. 3.2.

(b(i))[2]

Complete Fig. 3.2 by determining the mass melted per second for each power of the heater.

(b(ii).1)[3]

Use the data in the completed Fig. 3.2 to find a value for the specific latent heat of fusion $L$ of ice.

(b(ii).2)[2]

Use the data in the completed Fig. 3.2 to find the rate $h$ of thermal energy gained by the ice from the surroundings.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: The thermal energy needed to change the state/phase of unit mass at constant temperature

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