General Properties of Waves (Cambridge O Level Physics)

Fig. 8.1 represents a travelling wave at an instant in time.

Fig. 8.2 shows the main regions of the electromagnetic spectrum.

Fig. 6.1 shows crests of a water wave moving from left to right in a harbour.

   

(i)

On Fig. 6.1, draw three more crests to the right of point A.

[2]

       

(ii)

State the name of the wave process that occurs as the wave passes point A.

[1]

Fig. 6.2 shows the crests of another wave moving from left to right in a different part of the harbour. This wave moves from deep water to shallow water.

(iii)

Complete Table 6.1 to state whether each of the properties of the wave increases, decreases or stays the same as the wave passes into the shallow water.

[3]

Fig. 6.1 represents a transverse wave drawn full size. Point X represents a point on the wave.

  light

 sound

  radio

Sound is a longitudinal wave.

Sketch a representation of a longitudinal wave. On your sketch

A longitudinal wave passes from one medium into another medium. The speed of the wave is slower in the second medium.

State a typical value for the speed of sound in air.

A ray of light travelling in air strikes a glass block at an angle of 30° to the normal. The light slows down as it enters the glass block.

State and explain, in terms of wavefronts, what happens to the light.

Extended

The speed of light in this block of glass is 1.9 × 10⁸ m/s.

Calculate the refractive index of the glass.

refractive index = ...........................................................

Fig. 4.1 shows a wave on a rope and Fig. 4.2 shows a wave on a spring. Both waves are moving in the direction shown by the arrows.

Fig. 4.2

[1]

[1]
 

[1]

Table 4.1 shows some sentences that a student writes about waves.

His teacher places a ring around each mistake.

Write a suitable correction for each mistake in Table 4.1. One has been done for you.

Table 4.1

Describe a method of using water waves to demonstrate refraction.

Fig. 5.1 shows crests of a wave approaching a barrier where the wave is reflected.

On Fig. 5.1, draw three crests of the reflected wave.

The wave has a wavelength of 36 cm and a speed of 1.2 m/s.

 
Calculate the frequency of the wave.

frequency = .........................................................

Complete the following sentences.

 
An echo is the name for a reflected .................................................................. wave.

 
The waves that form an echo are a type of longitudinal wave. Longitudinal waves are made up of .................................................................. and rarefactions.

Extended

Fig. 6.1 shows wavefronts approaching a gap in a barrier.

(i)

On Fig. 6.1, draw three wavefronts to the right of the barrier.

[2]

 

(ii)

Fig. 6.2 shows the gap in the barrier increased to five times the gap in Fig. 6.1.

On Fig. 6.2, draw three wavefronts to the right of the barrier.

[2]

Describe, with a labelled diagram, an experiment using water waves that shows the reflection of wavefronts that occur at a straight barrier.

Green light of frequency 5.7 × 10¹⁴ Hz is travelling in air at a speed of 3.0 × 10⁸ m/s. The light is incident on the surface of a transparent solid.

Fig. 6.1 shows the wavefronts and the direction of travel of the light in the air.

The light travels more slowly in the transparent solid.

Explain, in terms of the wavefronts, why the light changes direction as it enters the solid. You may draw on Fig. 6.1 as part of your answer.

The refractive index of the transparent solid is 1.3.

A group of students want to determine the speed of sound in air.

Describe a method they can use. State the measurements they need to make.