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 melting ice that is held in a funnel, as shown in Fig. 3.1. The heater is switched on and, when the ice is melting at a constant rate, the mass $m$ of ice melted in $5.0$ minutes is measured, together with the heater power $P$. The power $P$ is then increased. A fresh reading for the mass $m$ of ice melted in $5.0$ minutes is taken when the ice is again melting at a constant rate. The data for the power $P$ and the mass $m$ are shown in Fig. 3.2.

(b(i))[2]

Complete Fig. 3.2 to determine the mass melted per second for each heater power.

(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 determine the rate $h$ at which the ice gains thermal energy 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: Energy needed to change the state/phase of a unit mass while the temperature remains constant

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