Download Power Calculations GCSE

Power Calculations
Power = current x potential difference
Power = current2 x resistance
2
R
1. Find the power:
a) power = ?
current = 4 A
pd = 30 V
b) power = ?
current = 12 A
pd = 6 V
(1)
a) power = ?
current = 3mA = _______A
pd = 100 V
(1)
(1)
2. Find the power:
c)
power = ?
current = 5 A
resistance = 12 Ω
d) power = ?
current =2 A
resistance = 200 Ω
(1)
a) power = ?
current = 4 A
resistance = 5KΩ = ______Ω
(1)
(1)
3. Find the unknown quantity:
a) power = 500 W
current = 4 A
pd = ?
a) power = 12 kW = _______W
current = 10 A
pd = ?
(1)
(1)
a) power = 200W
current = 5 mA
pd = ?
(1)
4 a What is the power of a 12 V, 50 A light?
(1 mark)
b What is the power of a bulb rated at 5 A, 6 V?
(1 marks)
c A 600 W electric heater is connected to a 120 V source. Calculate its current.
(2 marks)
d What is the power of an unknown device if a current of 35 mA flows through it when it is
connected to a 3 V supply?
(2 marks)
Extra Challenge:
5 A microwave oven has a power of 1800 W and the potential difference applied from the
mains is 230 V. What are its current and resistance?
(3 marks)
6
A device has a resistance of 11 Ω and a current of 12 A. What is it power and potential
difference?
(3 marks)
Score
Percentage
RAG