was the change in temperature of the water? heat was supplied to the at a rate of 543·4 joules per second, how long did it take to heat the water? 8. The temperature of 2 kg of steel is raised by 10 It takes 3 minutes for an electric 0C. heater connected to the mains (230 V) to do this. is the minimum energy supplied to the no energy losses, what is the power rating of the heater? current is drawn by the heater? 9. A 500 g mass of copper is heated by a 40 W immersion heater while a 500 g mass of steel is heated by a 50 W heater. The initial temperature of each block is 20 Which 0C. block is the first to reach a temperature of 80 You can assume that there are no oC? energy losses. 10. 80 g of alcohol at 20 is heated by an electric heater for 6 minutes until it reaches its 0C boiling point of 65 The heater operates at 230 V and draws a current of 125 mA. oC. much electrical energy is used by the heater? much heat energy is absorbed by the alcohol? much energy was to the environment? ‘lost’ Revision Questions National 4 level
was the change in temperature of the water? heat was supplied to the at a rate of 543·4 joules per second, how long did it take to heat the water? 8. The temperature of 2 kg of steel is raised by 10 0C. It takes 3 minutes for an electric heater connected to the mains (230 V) to do this. is the minimum energy supplied to the no energy losses, what is the power rating of the heater? current is drawn by the heater? 9. A 500 g mass of copper is heated by a 40 W immersion heater while a 500 g mass of steel is heated by a 50 W heater. The initial temperature of each block is 20 0C. Which block is the first to reach a temperature of 80 oC? You can assume that there are no energy losses. 10. 80 g of alcohol at 20 0C is heated by an electric heater for 6 minutes until it reaches its boiling point of 65 oC. The heater operates at 230 V and draws a current of 125 mA. much electrical energy is used by the heater? much heat energy is absorbed by the alcohol? much energy was ‘lost’ to the environment? Revision Questions National 4 level