Chapter 11: Wave Motion

Question 1

Define a transverse wave

Answer 1

A wave in which the wave particles oscillate in a direction perpendicular to the direction of wave propagation

Question 2

Define a longitudinal wave

Answer 2

A wave in which the particles oscillate in a direction parallel to the direction of wave propagation

Question 3

State the formula for wave speed

Answer 3

v = fλ

Question 4

State the formula for phase difference (Φ)

Answer 4

Φ = (2π x) / λ

Question 5

Define a compression in a longitudinal wave

Answer 5

A region where the air molecules are closest together such that the pressure is at a maximum value

Question 6

Define a rarefaction in a longitudinal wave

Answer 6

A region where the air molecules are furthest apart from each other such that the pressure is at a minimum value

Question 7

Define intensity

Answer 7

The rate of flow of energy per unit area perpendicular to the direction of the wave

Question 8

State the relationship between Intensity (I) and Amplitude (A)

Answer 8

I ∝ A²

Question 9

State the relationship between Intensity (I) and distance (r)

Answer 9

I ∝ (1/ r²)

Question 10

State the relationship between amplitude and distance

Answer 10

A ∝ 1/r

Question 11

Define polarisation

Answer 11

A process by which a wave’s oscillation are made to occur in a single plane only which is perpendicular to the direction of the propagation of energy

Question 12

State Malus’s Law

Answer 12

I = I₀cos²θ

Question 13

a wave

Answer 13

a means of energy transfer via oscillations

Question 14

speed of a wave

Answer 14

distance moved per unit time of wave energy

Question 15

why a sound wave cannot be polarised

Answer 15

Sound wave is a longitudinal wave, only transverse waves can be polarised, as the vibration of wave particle is parallel to wave propagation