Physics 9702 · AS & A Level · Characteristics of alternating currents

Characteristics of alternating currents — practice question

A radio station sends out an amplitude-modulated wave to carry music.
(a(i))[2]

State the meaning of an amplitude-modulated (AM) wave.

(a(ii))[2]

Give two reasons why the transmitted wave is modulated rather than sending the information signal directly as a radio wave.

(b(i))[2]

The way amplitude $A$ changes with frequency $f$ for the transmitted wave is shown in Fig. 11.1. For this transmission, find the wavelength of the carrier wave.

(b(ii))[1]

Find the bandwidth.

(b(iii))[1]

Find the maximum frequency, in Hz, of the transmitted audio signal.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: the amplitude of the carrier wave varies according to the displacement of the information signal

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