Heating and cooling

Try your hand at some physics problems based on heating and cooling set by St John’s Physics tutor Professor Tony Weidberg

Q: You want to heat a cold room using a simple electric bar heater. This consists of one conducting wire connected to the mains via a plug. In order to maximise the power, should you make the wire thinner or thicker?

Q: Consider a glass of water with a block of ice floating on the surface. What happens to the level of the water when the ice melts?