Physics - Features of waves

Question 1

Define waves

Answer 1

Waves are vibrations that transfer energy from place to place.

Waves can be longitudinal or transverse.

Question 2

Give two examples of transverse waves

Answer 2

1. All forms of electromagnetic waves
2. Water waves
3. Seismic S waves

Question 3

Give two examples of longitudinal waves

Answer 3

1. sound waves
2. seismic P waves

Question 4

Considering transverse waves, explain what amplitude is

Answer 4

As waves travel, they set up patterns of disturbance.

The amplitude of a wave is its maximum disturbance from rest (its undisturbed position).

Question 5

Considering transverse waves, explain what wavelength is

Answer 5

The wavelength (λ) of a wave is the distance between a point on one wave and the same point on the next wave.

It is often easiest to measure this from the crest (top) of one wave to the crest (top) of the next wave

Question 6

Considering transverse waves, explain what frequency is

Answer 6

The frequency of a wave is the number of cycles of a wave that occur in one second.

The unit of frequency is the hertz (Hz).

In the picture there are 4 wavelengths (full cycles) of the wave in one second, so the frequency is 4 Hz

Question 7

A ray of light hits a mirror.
The angle of incidence is 48 degrees

What is the angle of reflection?

Answer 7

The angle of incidence is the angle that the light hits the mirror from a line which is at right angles to the mirror (the dotted line in the picture - called the ‘normal’).

The law of reflection says that the angle of incidence is the same as the angle of reflection.

Question 8

Explain refraction

Answer 8

Waves change speed when they pass across the boundary between two different substances, such as light waves refracting when they pass from air to water.

This causes them to change direction and this effect is called refraction.

Question 9

What is the

electromagnetic spectrum

Answer 9

The electromagnetic spectrum is a group of seven types of wave that are made up from electric and magnetic fields.

The properties of the waves in the spectrum depend on their wavelength and frequency.

Question 10

List the seven types of electromagnetic radiation, in the right order from the lowest frequency to the highest frequency

Answer 10

Remember it using

Rich Men In Venice Use X-Ray Guns

• *R**adio waves
• *M**icrowaves
• *I**nfrared
• *V**isible light
• *U**ltraviolet
• *X**-rays
• *G**amma rays

Question 11

Give a formula used to calculate the speed of a wave, using frequency and wavelength

Answer 11

v = f x λ

v - Speed in metres per second

f - frequency in hertz, Hz

λ - (lambda) wavelength in metres

Question 12

Give a formula to calculate speed of waves using distance and time

Answer 12

Question 13

What is the difference between a

geosynchronous satellite and

a geostationary satellite

Answer 13

A geosynchronous satellite travels around the earth and returns to exactly the same position every 24 hours.

A geostationary satellite orbits in the same way that the earth rotates so that it stays in exactly the same place above the earth at all times - that means satellite dishes communicating with geostationary satellites don’t need to be moved.

Question 14

What sort of electromagnetic radiation is used to communicate with satellites

Answer 14

Microwaves