Definitions

Question 1

Define transverse wave

Answer 1

A wave which has oscillations perpendicular to the direction of energy transfer.

Question 2

Define longitudinal wave.

Answer 2

A wave which has oscillations parallel to the direction of energy transfer.

Question 3

Define progressive wave.

Answer 3

A wave which oscillates through space (matter or a vacuum) and transfers energy but not matter.

Question 4

Define stationary wave.

Answer 4

A wave that remains in a constant position with no net transfer of energy, created by two progressive waves of the same frequency and amplitude superposing.

Question 5

Define amplitude.

Answer 5

Maximum displacement from the equilibrium position in the positive or negative direction (metres)

Question 6

Define wavelength.

Answer 6

The distance between two points in phase on adjacent waves. The length of one complete wave (metres).

Question 7

Define frequency.

Answer 7

The number of wavelengths passing a given point per unit time (Hertz).

Question 8

Define period of oscillation.

Answer 8

The time taken for one whole wavelength to pass a given point= 1/frequency. (seconds)

Question 9

Define wave speed.

Answer 9

The distance travelled by a wave per unit time (ms^-1)

Question 10

Define phase difference.

Answer 10

The difference between displacements of particles along a wave/on different waves (degrees or radians).

Question 11

Define coherent.

Answer 11

Two waves with a constant phase difference between them.

Question 12

Define superposition.

Answer 12

The overlap of two waves at a point in space.

Question 13

Define interference.

Answer 13

The superposition of two progressive waves from two coherent sources.

Question 14

Define constructive interference.

Answer 14

Superposition of two waves in phase, so that the resultant wave has a greater amplitude than the original two.

Question 15

Define destructive interference.

Answer 15

Superposition of two waves in antiphase, so that the waves cancel each other out and the resultant amplitude is smaller than the original waves.

Question 16

Define path difference.

Answer 16

The difference in the path traversed by two waves

Question 17

Define node.

Answer 17

A point on a standing wave where the amplitude is 0- caused by the superposing waves interfering destructively.

Question 18

Define antinode.

Answer 18

A point on a standing wave where the amplitude is at its maximum- caused by the superposing waves constructively interfering.

Question 19

Define fundamental frequency.

Answer 19

The lowest frequency of a stationary wave.

Question 20

Define harmonics.

Answer 20

A wave whose frequency is a positive integer multiple of the fundamental frequency of a periodic signal. Fundamental frequency is the 1st harmonic.

Question 21

Define refraction.

Answer 21

The change in direction or propagation of any wave as a result of it travelling different speeds at different points along the wave front.

Question 22

Define reflection.

Answer 22

Change in direction of a wavefront at a boundary between two media so that the wavefront returns to the medium from which ir originated.

Question 23

Define total internal reflection.

Answer 23

Complete reflection of a ray of light from a boundary back into the medium from which it originated. Only occurs if the angle of incidence is greater than the critical angle.

Question 24

Define diffraction.

Answer 24

Waves spreading out when they travel through a gap or past an obstacle. Does not change the speed, wavelength or frequency.

Question 25

Define polarisation.

Answer 25

The process only transverse waves undergo which causes particles in a wave to oscillate in only one plane.

Question 26

Define plane polarised.

Answer 26

A transverse wave which has undergone polarisation and has oscillations which only occur in one plane.

Question 27

Define partial polarisation.

Answer 27

A wave which has oscillations in more than one plane, but the intensity of the oscillations in one plane is greater.

Question 28

Define intensity.

Answer 28

The quantity of energy that a wave conveys per unit time across a surface per unit area.