Waves

Question 1

What is a transverse wave

Answer 1

Propagation is perpendicular to direction of energy transfer, no need of medium

Question 2

What is a longitudinal wave

Answer 2

Propagation is parallel to direction of energy transfer, needs a medium

Question 3

Examples of transverse waves

Answer 3

Light, secondary seismic waves, waves on a rope

Question 4

Examples of longitudinal waves

Answer 4

Sound waves, mechanical waves

Question 5

What is plane polarised

Answer 5

When oscillations of a wave are in only one plane, perpendicular to direction of energy transfer

Question 6

Examples of unpolarised light

Answer 6

Candle or filament lamp

Question 7

When is light intensity at minimum if two polaroid filters are placed between light

Answer 7

Filters are crossed at 90 degrees

Question 8

Uses of polaroids

Answer 8

Polaroid glasses to reduce glare from glass (drivers)

Question 9

What is amplitude

Answer 9

Maximum displacement from equilibrium position

Question 10

What is wavelength

Answer 10

Length of a one whole wave cycle

Question 11

What is a period

Answer 11

Time for one wave cycle to pass

Question 12

What is frequency

Answer 12

Number of wave cycles per second

Question 13

What is phase difference

Answer 13

Fraction of a cycle between the vibrations of the two particles on a wave, measured in radians or degrees

Question 14

Do waves travel faster or slower in shallow water

Answer 14

Waves travel slower in shallow water

Question 15

When is diffraction at its optimum

Answer 15

When the gap is closest to the wavelength of the wave

Question 16

What is superposition

Answer 16

When two waves meet, the total displacement is equal to the sum of displacements from each wave

Question 17

What is a stationary wave

Answer 17

A wave that doesn’t transfer energy, formed when two progressive waves pass through each other of same wavelength, composed of nodes and anitnodes

Question 18

What are nodes

Answer 18

Points on a progressive/stationary wave with 0 displacement

Question 19

When does interference occur

Answer 19

When waves of constant frequency and phase difference passes through each other

Question 20

Examples of stationary waves

Answer 20

Formed on string, microwaves and sound waves

Question 21

What are antinodes

Answer 21

Maximum amplitude between nodes

Question 22

What is unpolarised light

Answer 22

Light with oscillations in many different directions, perpendicular to direction of energy transfer

Question 23

Reflected light are…

Answer 23

Plane-polarised

Question 24

How are stationary waves formed on a string

Answer 24

Waves of the same frequency and wavelength reflect of one side. Waves now travelling in opposite directions interfere

Question 25

What is a progressive wave

Answer 25

Wave that transfers energy from one point to another

Question 26

What must be satisfied about a string fixed on both ends for a stationary wave

Answer 26

L = n X (lambda/2)

Question 27

Explain why the minimum intensity between the 2 and 3 maximums is not zero

Answer 27

Intensity decreases with distance, one wave travels further than the other, amplitudes are not equal to each other

Question 28

What occurs when the width of the slits are increased

Answer 28

The intensity of light increases

Question 29

With reference to resonance, why does changing the length affect the loudness of the sound

Answer 29

Air has a natural frequency of vibration, when the fork frequency equals the natural frequency of vibration maximum loudness, when they are not equal volume drops

Question 30

How to find phase difference in a STATIONARY WAVE

Answer 30

0 if particles are between adjacent nodes or separated by an even number of nodes. 180° if the two particles are separated by an odd number of nodes.

Question 31

Which electromagnetic wave has a wavelength, similar to the diameter of a nucleus

Answer 31

Gamma

Question 32

What changes when light refracts

Answer 32

Speed and wavelength

Question 33

What condition is necessary for interference to be observed

Answer 33

Constant phase difference

Question 34

Describe the motion of a particle on a transverse wave

Answer 34

Perpendicular to direction of energy transfer (then talk about up, down directions)