Question
There is a current I in a resistor of resistance R for a time t. The potential difference across the resistor is V.
Which equation gives the energy E transferred by the resistor?
A E = IR
B E = IV
C E = IRt
D E = IVt
Answer/Explanation
Ans: D
Question
There is a current of 5.0 A in a resistor.
The potential difference (p.d.) across the resistor is 24 V.
How much energy is transferred in the resistor in 1.0 minute?
A 5.0 J
B 120 J
C 290 J
D 7200 J
Answer/Explanation
Ans: A
Question
An air-conditioning unit, a lamp and an electric fire all receive electrical energy from the mains supply.
From which of these devices is all this energy eventually transferred to the surroundings?
Answer/Explanation
Ans: A
Question
An air-conditioning unit, a lamp and an electric fire all receive electrical energy from the mains supply.
From which of these devices is all this energy eventually transferred to the surroundings?
Answer/Explanation
Ans: A
Question
A water heater is connected to a 230 V supply and there is a current of 26 A in the heater.
It takes 20 minutes to heat the water to the required temperature.
How much energy is supplied by the heater?
A 6.0 × 
J
B 1.0 ×
J
C 1.2 × 
J
D 7.2 × 
J
Answer/Explanation
Ans: D