Chapter 11 Waves 1

Question 1

What is a progressive wave?

Answer 1

It is a wave that moves through matter or a vacuum and It transfers energy without transferring matter.

Question 2

What is a transverse wave?

Answer 2

It is a wave that oscillates perpendicular to the direction of travel of the wave.

Question 3

What are some examples of transverse waves?(4)

Answer 3

Waves on the surface of water Any electromagnetic wave Waves on a stretched string Swaves produced by earthquakes

Question 4

What is a peak and what is a trough?

Answer 4

These are both the maximum displacement of a particle from equilibrium. Peak is the positive displacement and a trough is the negative displacement

Question 5

What is a longitudinal wave?

Answer 5

It is a wave that oscillates parallel to the direction that the waves travel

Question 6

What are some examples of longitudinal waves?(2)

Answer 6

Sound pwaves from earthquakes

Question 7

What is displacement?

Answer 7

It is the distance that a particle is from equilibirum

Question 8

What is amplitude?

Answer 8

It is the maximum displacement from equilibrium

Question 9

What is wavelength?

Answer 9

This is the minimum distance between two identical points on a wave

Question 10

What is the period of oscillation?

Answer 10

This is the time it takes for one oscillation

Question 11

What is the frequency?

Answer 11

It is the number of wavelengths passing a point in a second, also the number of oscillations per second

Question 12

What is wave speed?

Answer 12

It is the distance travelled by a wave per unit of time

Question 13

What is the wave equation?

Answer 13

V = Fλ

Question 14

What is the equation to find frequency from time period?

Answer 14

f = 1/t f = frequency t = timeperiod

Question 15

What is the law of reflection?

Answer 15

The angle of incidence is equal to the angle of reflection

Question 16

What is refraction?

Answer 16

This is when light changes the medium it flows through and due to the change in speed it changes direction

Question 17

What happens if the speed of the wave slows down when changing medium?

Answer 17

Refract towards the normal

Question 18

What happens if the speed of the wave increases when changing medium?

Answer 18

It refracts away from the normal

Question 19

What happens if a) light or b) sound enters a denser medium?

Answer 19

a) When light enters a denser medium it slows down b) when sound enters a denser medium it speeds up

Question 20

What happens when light enters water from air?

Answer 20

It bends towards the normal and the wavelength gets smaller

Question 21

What is diffraction and what is the property unique to?

Answer 21

Diffraction is unique to waves and is when it spreads out as it passes through a gap

Question 22

What is polarisation? and plane polarisation?

Answer 22

This is when particles oscillate in a single direction. along a single plane

Question 23

What does unpolarised light look like?

Answer 23

It is light that oscillates in multiple directions.

Question 24

What does the amount of diffraction rely on?

Answer 24

It relies on the size of the gap that it passes through and the wavelength

Question 25

What does partial polarisation? and when does it happen?

Answer 25

This is when light oscillates in more than one plane but it not fully unpolarised. its sort of half way between This happens when light reflects off a surface like a lake

Question 26

What is intensity and what is its equation and units?

Answer 26

It is the radiant power passing through a surface per unit of area. I = P / A Units: Wm^-2

Question 27

What happens to the intensity if the distance from a source doubles?what is the general equation

Answer 27

The intensity is 1/4 I ∝ 1/r^2

Question 28

How is amplitude and intensity related?

Answer 28

Intensity ∝ (amplitude)^2

Question 29

What is special about electromagnetic waves vs other waves?

Answer 29

It does not need a medium to pass through

Question 30

What is the wave equation for electromagnetic waves?

Answer 30

c = fλ

Question 31

What is the speed of light? and symbol?

Answer 31

c = 3x10^8

Question 32

What is a polarising filter and how does it work?

Answer 32

It is a filter that polarises light. It acts like a gate and so only the light that is oscillating with the direction of the rails is allowed through. Light that oscillated differently is simply cut out

Question 33

What is a use for polarising filters and explain how this is usefull?

Answer 33

It is used for ariels where the wave is polarised to reduce interference between different transmitters.