Waves

Question 1

What do waves transfer

Answer 1

Energy but not matter

Question 2

What waves can be polarised

Answer 2

Transverse waves

Question 3

How does polarisation provide evidence for the nature for transverse waves

Answer 3

Polarisation can only occur if a waves oscillations are perpendicular to its direction of travel

Question 4

What is a polarise wave

Answer 4

A wave that only oscillated in one place

Question 5

Define superposition

Answer 5

The displacements of two waves are combined as they pass each other

Question 6

Define constructive interference

Answer 6

Occurs when 2 waves have displacement in the same direction

Question 7

Define destructive interference

Answer 7

Occurs when one wave has +ve displacement and the other has -ve displacement

Question 8

Define total destructive interference

Answer 8

The 2 waves have equal but opposite displacements

Question 9

When is a stationary wave formed

Answer 9

Formed from the superposition of two progressive waves travelling in opposite directions in the same plane, with same frequency, wave length and amplitude

Question 10

Is energy transferred by a stationary wave

Answer 10

No

Question 11

What are antinodes

Answer 11

Regions of maximum displacement

Question 12

When do antinodes form

Answer 12

When waves meet in phase so constructive interference occurs

Question 13

What are nodes

Answer 13

Regions of no displacement

Question 14

When do nodes form

Answer 14

When waves meet completely out of phase, so destructive interference occurs

Question 15

Define the first harmonic

Answer 15

Te lowest frequency at which a stationary wave forms

Question 16

How do you form the 2nd harmonic from the 1st harmonic

Answer 16

Double the frequency

Question 18

Define path difference

Answer 18

The difference in distance travelled by 2 waves

Question 19

What makes a coherent light source

Answer 19

Same frequency, wavelength and fixed phase difference

Question 20

How do you make a monochromatic light source for youngs double slit experiment

Answer 20

Place a single slit in front of the double slit and add a filter

Question 21

Why should you place a single slit in front of the double slits

Answer 21

Makes the wave have a fixed phase difference

Question 22

How big do the gaps have to be for diffraction to occur

Answer 22

Similar in size to the wavelength

Question 23

Describe the procedure for young’s double slit experiment

Answer 23

• shine a coherent light source through 2 slits so light diffracts

Question 24

What do each slit act as

Answer 24

A coherent point source

Question 25

What observations are made when diffraction occurs

Answer 25

Pattern of light and dark fringes

Question 26

When are light fringes formed

Answer 26

When light meets in phase and interferes constructively

Question 27

Hen are dark fringes formed

Answer 27

When light meets completely out of phase and interferes destructively

Question 28

How is the diffraction pattern different when white light is used instead of monochromatic light

Answer 28

- wider maxima and less intense diffraction pattern - central white fringe with alternating bright fringes - violet closes, red furthest

Question 29

Give 3 safety precautions for lasers

Answer 29

- don’t point them at people -wear safety goggles - don’t shine them at reflective surfaces

Question 30

How can youngs double slit experiment be altered for sound waves

Answer 30

Use 2 speakers connected to a signal generator. Intensity of wave can be measured using a microphone

Question 31

How does youngs double slit experiment provide evidence for wave nature of light

Answer 31

Diffraction and interference are wave properties