Waves Definitions

Question 1

Progressive Wave

Answer 1

Distributes energy from source point to surrounding area, by moving energy in form of vibrating particles.

Question 2

Displacement

Answer 2

Distance from equilibrium position in particular direction in metres.

Question 3

Amplitude

Answer 3

Maximum displacement, metres

Question 4

Wavelength

Answer 4

Minimum distance between 2 points in phase on adjacent waves.

Question 5

Frequency

Answer 5

No wavelengths passing a given point per unit time, hertz

Question 6

Time period

Answer 6

Time for 1 complete oscillation to pass, seconds

Question 7

Transverse Wave

Answer 7

Oscillations are perpendicular to direction of energy transfer

Question 8

Longitudinal Wave

Answer 8

Oscillations are parallel to direction of energy transfer.

Question 9

Phase Difference vs Path Difference

Answer 9

Difference between the displacement particles along a wave (in degrees or radians) vs fractions of a wavelength

Question 10

Reflection

Answer 10

Wave changes direction at boundary between 2 diff media, remain for in original medium.

Question 11

Refraction

Answer 11

Wave changes speed when passing across the boundary between 2 diff media and change direction
Increase speed, bend towards normal
Wavelength changes not frequency

Question 12

Refractive Index

Answer 12

Ratio of velocity of light in a vacuum to take velocity in a specified medium.

Question 13

Total Internal Reflection

Answer 13

Occurs at boundary between 2 diff media and all light is reflected back to original medium.

Question 14

Diffraction

Answer 14

Waves pass through gap or travel around obstacle and spread out.

Question 15

Polarisation / plane polarised

Answer 15

Particles oscillate along 1 direction only

Transverse wave

Question 16

Electromagnetic Waves

Answer 16

Transverse waves, electric and magnetic fields oscillating at right angle to each other.

Question 17

Principle of superposition

Answer 17

When 2 or more waves cross the resultant displacement equals the vector sum of the individual displacements

Question 18

Coherent waves

Answer 18

Same wavelength and frequency and fixed phase difference between them

Question 19

Constructive vs Destructive interference

Answer 19

Crest to crest, trough to trough
(1 wavelength or 360 or 2pi)

vs

crest to trough
(1/2 wavelength or 180 or pi)

Question 20

Line spectrum

Answer 20

Light emitted from excited isolated atoms produce a line spectrum