Waves

Question 1

What is a progressive wave?

Answer 1

A wave that transports energy without transporting material (and is made up of particles of a medium oscillating.

Question 2

Define amplitude.

Answer 2

The maximum displacement from the equilibrium position.

Question 3

Define frequency.

Answer 3

The number of COMPLETE oscillations passing through a point per second.

Question 4

Define wavelength.

Answer 4

The length of one complete oscillation.

Question 5

Define period.

Answer 5

The time taken to complete one full oscillation

Question 6

Define phase and suggest its units.

Answer 6

The position of a certain point on a wave cycle. Its units are radians, degrees, or fraction of a wave cycle.

Question 7

Define phase difference.

Answer 7

The cycle difference between two waves at the same point

Question 8

What is a transverse wave?

Answer 8

The oscillation of particles is perpendicular to the direction of energy transfer.

Question 9

What is a longitudinal wave?

Answer 9

The oscillation of particles is parallel to the direction of energy transfer.

Question 10

What type of waves are electromagnetic waves?

Answer 10

Transverse (waves)

Question 11

Define node.

Answer 11

A position of zero displacement in a stationary wave.

Question 12

Define antinode.

Answer 12

A position of maximum displacement in a stationary wave.

Question 13

What are coherent waves?

Answer 13

Waves that have the same frequency, same wavelength, and have a constant phase difference.

Question 14

What is wave speed?

Answer 14

The distance travelled by a wave per second.

Question 15

Which wave type can be polarised?

Answer 15

Transverse.

Question 16

What is superposition?

Answer 16

The adding together of wave displacements that occurs when two separate sources overlap. The displacements add mathematically.

Question 17

Define constructive interference.

Answer 17

When two waves in phase and travelling in the same direction interfere, adding their amplitudes.

Question 18

Define destructive interference.

Answer 18

When two waves in antiphase (180 degrees out of phase) interact and cancel each other out.

Question 19

Define stationary wave.

Answer 19

A wave that stores energy instead of transferring it.

Question 20

What is the fundamental frequency/first harmonic?

Answer 20

The lowest frequency for a standing wave to form.

Question 21

Define diffraction.

Answer 21

The spreading out of waves when they pass through a small gap OR around an obstacle.

Question 22

What type of light will displays an interference pattern?

Answer 22

Monochromatic light.

Question 23

Define refraction.

Answer 23

When a wave changes speed when it enters a new medium.

Question 24

If a wave enters a medium more optically dense, what happens to the wave?

Answer 24

The wave slows down and bends towards the normal.

Question 25

If a wave enters a medium less optically dense, what happens to the wave?

Answer 25

The wave speeds up and bends away from the normal.

Question 26

What is the critical angle?

Answer 26

The angle of incidence when total internal reflection occurs( angle of refraction is 90 degrees to the normal)

Question 27

What is optical fibre?

Answer 27

A thin glass fibre through which signals are passed through.

Question 28

What are the two main parts of step-index optical fibres?

Answer 28

1. A core made from a high-refractive index material.
2. Cladding made from a low-refractive index material.

Question 29

What are the two components of electromagnetic waves?

Answer 29

Magnetic and electric oscillations that are perpendicular to each other.

Question 30

Define polarisation.

Answer 30

The restriction of a wave so that it can only oscillate in one direction.

Question 31

What conditions are needed for a stationary wave to be produced?

Answer 31

The waves need be travelling in opposite directions, and have the same frequency, wavelength, and amplitude.