Cost of  Electricity – Practice Exam Questions
1.  (a)	In the table below three electrical appliances are listed with their power ratings and the number of hours they are used each week.											

(i)	Complete the table by inserting the number of kWh used by each appliance each week.				(3)
(ii)	Which appliance would cost the least to run per week?								(1)
(iii)	The cost of running a toaster is 8p per week.  How much does it cost to run the kettle each week?			(2)

Device	Power	
Toaster	1.2 kW	
Fan	30 W	
Personal Stereo	10 W	
2. (a)	The power of several devices is given in the table.  Which one of the devices will transfer the most energy in 10 minutes?				(1)

(b)	The diagrams show the readings on a domestic electricity meter in April and July.

(i)	How many Units (kWh) of electricity were used between the two meter readings?				(1)
(ii)		One Unit costs 6p.  Use the following equation to calculate the cost of the electrical energy used between the two meter readings. Show clearly how you work out your answer.
total cost = number of Units x cost per Unit									(2)
(c)	A 3000 watt electric cooker is switched on for 2 hours.  Use the following equation to calculate the number of Units of energy transferred by the cooker. Show clearly how you work out your answer.
     			  				(2)

5.  (a) The power of the fan heater is 2.75 kW. Calculate how many kilowatt hours (kWh) of energy are transferred when the fan heater is used for 6 hours.								          	   (2)
(b)	How much will it cost to use the fan heater for 6 hours if one Unit of electricity costs 7p?				(2)