Topic 4 Waves

Question 1

What is wavelength?

Answer 1

distance between the same points on two consecutive waves (waves following each other)

Question 2

What is amplitude?

Answer 2

Distance from the equilibrium line to the crest (highest part of wave)

Question 3

What is a period?

Answer 3

Time taken for a whole wave to completely pass a point

Question 4

What is a wavefront

Answer 4

Imaginary surface representing corresponding points of a wave that vibrate in unison

Question 5

In which direction do transverse waves travel

Answer 5

perpendicular to the direction of energy transfer

Question 6

In which direction do longitudinal waves travel?

Answer 6

Parallel to the direction of energy transfer

Question 7

Examples of transverse waves

Answer 7

Water, light, radio, microwaves, seismic S waves

Question 8

Examples of longitudinal waves

Answer 8

sound, seismic p waves

Question 9

Where do transverse waves travel

Answer 9

Travel through a vacuum

Question 10

Where do longitudinal waves travel

Answer 10

Through a medium

Question 11

Why is a smoother surface better for reflection?

Answer 11

The smoother the surface the stronger the reflected wave

Question 12

What happens when light is reflected on a rough surface?

Answer 12

rough surfaces will scatter light in all directions so appear matte and not reflective

Question 13

What is the equation from finding the velocity?

Answer 13

Frequency x wavelength

Question 14

What is the equation for finding the wavespeed?

Answer 14

Frequency x wavelength

Question 15

What is frequency?

Answer 15

Number of waves that pass a single point per second

Question 16

What is refraction

Answer 16

When waves pass from one medium to another

Question 17

What happens if a waves passes through a more optically dense medium

Answer 17

The wave will be refracted at the boundary and will change direction to bend towards the normal
- the speed will decrease
- and the wavelength will decrease

Question 18

What are the effects of wavelength

Answer 18

Different substances may absorb, transmit, refract or reflect waves depending on their wavelength

Question 19

How is the velocity of sound in air measured

Answer 19

• make a noise 50m from a solid wall and record how long it takes for an echo to be heard
• use the speed = distance/time equation

Question 20

How is the velocity of ripples on a water surface measured

Answer 20

• use a stroboscope which has the same frequency as the water waves
• measure distance between the fixed ripples
• use velocity = frequency x wavelength