P7: General Properties of Waves

Question 1

What do waves do?

Answer 1

Transfer energy without transferring matter.

Question 2

Mechanical waves

Answer 2

A vibration that travels through a substance.

Question 3

Longitudinal waves

Answer 3

Waves in which the vibrations are parallel to the direction of energy transfer.

Question 4

Transverse waves

Answer 4

Waves in which the vibrations are perpendicular to the direction of energy transfer.

Question 5

Electromagnetic waves

Answer 5

Can travel through a vacuum, no medium is needed.

Question 6

Examples of mechanical waves

Answer 6

sound, water, seismic

Question 7

Examples of electromagnetic waves

Answer 7

light, radio, micro

Question 8

Examples of Transverse waves

Answer 8

All electromagnetic waves

Question 9

Example of longitudinal waves

Answer 9

Sound

Question 10

Amplitude

Answer 10

Height of the wave crest.

Question 11

The bigger the amplitude of the waves…

Answer 11

…. the more energy the waves carry.

Question 12

Wavelength

Answer 12

The distance from one wavelength to the next.

Question 13

Frequency

Answer 13

The number of wave crests passing a fixed point every second.

Question 14

Speed of waves

Answer 14

Distance travelled by a wave crest every second.

Question 15

Wave speed (m/s) =

Answer 15

Frequency (Hz) x Wavelength (m)

Question 16

Straight waves

Answer 16

Plane waves

Question 17

Reflection

Answer 17

The change of direction in a light ray or wave at a boundary when a wave/ray stays in the incident medium.

Question 18

Refraction

Answer 18

The change of direction of a light ray when it crosses a boundary between two transparent substances.

Question 19

Diffraction

Answer 19

The spreading of waves when they pass through a gap or around the edges of an obstacle.

Question 20

The smaller the hole…

Answer 20

… The greater the diffraction

Question 21

When is diffraction most noticeable?

Answer 21

When the hole is the same size as the wavelength of the wave.

Question 22

What can diffraction cause?

Answer 22

Bad TV and Radio connection

Question 23

Interference

Answer 23

Reinforcement or cancellation of waves when two sets of identical waves overlap.

Question 24

When waves overlap crest to crest…

Answer 24

… constructive interference/ reinforcement takes place

Question 25

What waves overlap crest to trough…

Answer 25

… destructive interference/ cancellation takes place.