CAIE A-Level Physics AS 7 Waves Questions

Practise analysing progressive, transverse and longitudinal waves, speed, intensity, Doppler shifts, electromagnetic spectra, polarisation and filters.

Exam points

interpret wave quantities and graphs and use v = fλ to solve progressive-wave problems
analyse transverse and longitudinal wave behaviour, including graphical representations and phase
explain and calculate Doppler shifts for moving sound sources
classify electromagnetic waves by transverse behaviour, speed, wavelength and spectrum
analyse polarisation and calculate intensity transmission through filters

Covered syllabus points

7.1 Progressive waves 7.2 Transverse and longitudinal waves 7.3 Doppler effect for sound waves 7.4 Electromagnetic spectrum 7.5 Polarisation

[Maximum number: 5]

A progressive transverse wave travelling from left to right is shown at an instant in time in Fig. 4.1.

Fig. 4.1

R and T are points on the wave.

(a)

State the phase difference between the points R and T .
phase difference =

[ 1 ]

$270^{\circ}$

(b)

On Fig. 4.1, draw an arrow at point T to show the direction of movement of point T at the instant shown.

[ 1 ]

(c)

The horizontal distance between R and T is 0.62 cm , as shown in Fig. 4.2.

Fig. 4.2 (not to scale)

The speed of the wave is $0.27 \mathrm{~ms}^{-1}$ .
Calculate the frequency of the wave.
frequency = Hz

[ 3 ]

$v=f \lambda$

or
$v=\lambda / T \text { and } f=1 / T$ $\begin{aligned} \text { wavelength } =0.62 \times 10^{-2} \times(4 / 3) ( \left.=0.83 \times 10^{-2} \mathrm{~m}\right) \end{aligned}$ $\begin{aligned} f =0.27 /\left(0.83 \times 10^{-2}\right) =33 \mathrm{~Hz} \end{aligned}$

[Maximum number: 1]

A guitar string is plucked.
Which statement describes the resulting waves?

Longitudinal waves on the string cause longitudinal waves in the air.

Longitudinal waves on the string cause transverse waves in the air.

Transverse waves on the string cause longitudinal waves in the air.

Transverse waves on the string cause transverse waves in the air.

[Maximum number: 1]

An ambulance siren emits a sound with a single frequency f.
The ambulance travels towards, passes close to, and then travels away from a stationary observer.

Which statement describes the frequency of the sound detected by the observer as the ambulance passes the observer?

equal to f and decreasing

equal to f and increasing

greater than f and constant

less than f and constant

[Maximum number: 1]

An electromagnetic wave is travelling through a vacuum.
What could be the wavelength and period of the electromagnetic wave?

wavelength

period

$1.2 \times 10^{-10} \mathrm{Tm}$

2.5 Ms

1.2 pm

$2.5 \times 10^{11} \mathrm{Gs}$

$1.2 \times 10^{2} \mathrm{pm}$

$4.0 \times 10^{-10} \mathrm{~ns}$

$1.2 \times 10^{3} \mu \mathrm{~m}$

4.0 ns

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Covered syllabus points

Question 1

Question (a)

Question (b)

Question (c)

Question 2

Question 3

Question 4