Physics 5054 · O Level · Energy, work and power

Energy, work and power — practice question

A filament lamp rated at 75 W in an office is mistakenly left on for 63 hours while the office is shut.
(a(i))[3]

Calculate the electrical energy supplied to this lamp in this period.

(a(ii))[1]

The lamp has an efficiency of 0.12 (12%). Calculate the energy given out by the lamp as light.

(b(i))[1]

The power station supplying electricity to the office burns oil as its fuel. State and explain whether oil is a renewable or a non-renewable source of energy.

(b(ii))[2]

Discuss one environmental effect of using oil as an energy source.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: From substitution, $E = Pt = 75 \times 63 \times 60$

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