One form of latent heat is the thermal energy needed to melt a solid. [Figure 4.1 shows an apparatus for measuring thermal energy. It consists of a glass funnel containing ice, covered by an insulator. A heater is placed beneath the ice, and a beaker collects melted water.]

1. (a)Define specific latent heat.[2]
2. (b)(i)Fig. 4.1 shows one method of measuring the thermal energy needed to melt ice. The ice is contained in a glass funnel and covered with an insulator. The heater is switched on and the ice melts. The specific latent heat of fusion of ice is 3.3 × 10⁵J/kg. Calculate the energy needed to melt 5.0 g of ice. energy = .....................................................[2][2]
3. (b)(ii)Before the heater is switched on, thermal energy from the room causes some of the ice to melt. Describe the process by which the ice gains thermal energy from the air.[1]

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