Physics 5054 · O Level · Electrical safety

Electrical safety — practice question

A filament lamp is positioned above a polished metal surface, as shown in Fig. 8.1.
(a(i))[1]

State the meaning of ‘efficiency’.

(a(ii))[1]

Suggest why a filament lamp has a very low efficiency.

(b)[2]

Use this information, together with the data in Table 8.1, to determine the efficiency of the LED.

(c(i))[2]

Describe what happens next.

(c(ii))[2]

Explain why a person is not protected when the live wire touches the shiny metal surface.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Total energy input / useful energy output

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