Physics Paper 1 IGCSE Edexcel Unit 3

1. State the relationship between wavespeed, frequency, and wavelength.

2. State the relationship between frequency and time period.

3. State the relationship between refractive angle, incident angle, and refractive index

4. State the relationship between the critical angle and the refractive index.

Answer explanation

1. v = fλ

2. f = 1/T

3. n = sini/sinr

4. sinc = 1/n

What are waves?

Answer explanation

Waves are a means of transferring energy from one place to another without matter being transferred; particles vibrate about fixed position.

Describe the difference between transverse and longitudinal waves.

Answer explanation

Transverse waves: particles vibrate perpendicular to the direction of wave propagation; EM waves, sea waves.

Longitudinal waves: particles vibrate parallel to the direction of wave propagation; sound waves.

1. Define amplitude.

2. Define wavefront.

3. Define frequency.

4. Define wavelength.

5. Define time period.

Answer explanation

1. 1. the maximum displacement of a particle from its equilibrium position.

2. 2. line connection points which are in phase and the same distance from the source.

3. 3. number of complete oscillations in one second

4. 4. distance between a particular point on a wave, and the same point on the next wave

5. 5. time taken for a complete wave cycle

How do amplitude and frequency relate to loudness and pitch?

Answer explanation

Higher amplitude = louder sound

Higher frequency = higher pitch

And vice versa.

Define the Doppler Effect.

Answer explanation

The change in frequency or wavelength of a wave signal, caused by the relative movement between the wave source and the observer.

What happens when a wave source is stationary?

Answer explanation

The observer receives the same frequency and wavelength from the source whether in front or behind it.

What happens when a wave source is moving towards an observer?

Answer explanation

Observer receives a higher frequency and shorter wavelength than the wave produced at the source.

Wavefronts get compressed;

Wavelength decreases so frequency increases;

Wavelength and frequency are inversely proportional given that wavespeed remains constant.

What happens when a wave source is moving away from an observer?

Answer explanation

Observer receives a lower frequency and longer wavelength than the wave produced at the source.

Wavefronts get spread out;

Wavelength increases so frequency decreases;

Wavelength and frequency are inversely proportional given that wavespeed remains constant.

What do all electromagnetic waves have in common?

Answer explanation

tranverse/transfer energy/travel at the speed of light in vacuum/can be reflected, refracted, diffracted