the cost of electricity

Question 1

what is power measured in?

Answer 1

watts (W) or kilowatts (KW)

A 5 KW appliance transfers 5000 J in 1 S

Question 2

what are the standard units of electrical energy?

Answer 2

kilowatt-hours (kWh) (not joules)

Question 3

what is a kilowatt-hour?

Answer 3

the amount of electrical energy used by a 1KW appliance left on for one hour

Question 4

what are the two formulas for calculating the cost of electricity?

Answer 4

no of units (kWh) used= power (in kW) X time (in hours)

cost= no of units X price per unit

Question 5

what is energy measured in?

Answer 5

Joules (J) 1 J is the amount of energy transferred by a 1 W appliance in 1 S