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

Characteristics of alternating currents — practice question

In radio communication, the bandwidth of an FM transmission is larger than the bandwidth of an AM transmission.
(a(i))[1]

State what bandwidth means.

(a(ii))[2]

State one benefit and one drawback of a greater bandwidth.

(b(i))[1]

A carrier wave with frequency $650\,\text{kHz}$ has a measured amplitude of $5.0\,\text{V}$. It is frequency modulated by a signal with frequency $10\,\text{kHz}$ and amplitude $3.0\,\text{V}$. The frequency deviation of the carrier wave is $8.0\,\text{kHz V}^{-1}$. Determine, for the frequency modulated carrier wave, the measured amplitude.

(b(ii))[2]

Determine the maximum and minimum frequencies.

(b(iii))[1]

Determine the shortest time between a maximum transmitted frequency and a minimum transmitted frequency.

(c)[1]

Determine the shortest time between a maximum and a minimum transmitted frequency.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: the frequency span of the signal

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