Waves

Question 1

displacement

Answer 1

distance in a stated direction of a particle in the wave from its mean or equilibrium position. Displacement is a vector quantity

Question 2

amplitude

Answer 2

the maximum displacement of a particle in the wave. It is a scalar.

Question 3

frequency

Answer 3

number of oscillations completed per unit time. 1 Hz is one oscillation per second

Question 4

intensity

Answer 4

the rate of transfer of energy per unit area normal to the direction of the wave. Unit is watts per square metre (Wm^-2)

Question 5

period

Answer 5

the time for one oscillation of a particle in the wave. The unit is second (s)

Question 6

wavelength

Answer 6

the distance moved by the wave energy during one complete oscillation of the source. m or λ

Question 7

transverse

Answer 7

type of wave in which particles oscillate perpendicularly to the direction of travel of the wave

Question 8

longitudinal

Answer 8

type of wave in which particles oscillate parallel to the direction of travel

Question 9

electromagnetic spectrum

Answer 9

range of electromagnetic waves. This includes radio waves, microwaves, infrared, visible light, ultraviolet, x-ray and gamma rays

Question 10

plane-polarised wave

Answer 10

only one direction of oscillation. Can only happen to transverse waves

Question 11

Malu’s Law

Answer 11

When plane polarised light hits an analyser, the intensity of light leaving it is proportional to cos^2 of angle between transmission axis of analyser and polariser