Chapter 4 - Waves

Question 1

What are the two types of waves?

Answer 1

Longitudinal waves and transverse waves.

Question 2

What are electromagnetic waves?

Answer 2

Waves with oscillating electric and magnetic fields.

Question 3

What are longitudinal waves?

Answer 3

Waves which oscillate parallel to the direction of energy transfer.

Question 3

When is a transverse wave polarised?

Answer 3

When oscillations stay in one plane only.

Question 3

What are transervse waves?

Answer 3

Waves which oscillate perpendicular to the direction of energy transfer.

Question 4

What do polarising filters affect?

Answer 4

Light intensity.

Question 5

What is the displacement of a vibrating particle?

Answer 5

The displacement from equilibrium position.

Question 6

What is the amplitude of a wave?

Answer 6

The maximum displacement of a vibrating particle. Distance between equilibrium position and peak or trough.

Question 7

What is the wavelength?

Answer 7

The distance between the same point on two adjacent waves. It is the complete cycle of a wave.

Question 8

What is the period of a wave?

Answer 8

The time for one complete wave to pass a fixed point.

Question 9

What is the frequency of a wave?

Answer 9

The number of complete waves passing a point per second, measured in Hz.

Question 10

Equation for frequency.

Answer 10

f = 1/T, where T is the period.

Question 12

What is the phase of a vibrating particle?

Answer 12

The fraction of the cycle the particle has completed since the start of the cycle.

Question 12

Wave speed equation.

Answer 12

Wave speed, c = frequency X wavelength

Question 13

What is the phase difference?

Answer 13

The fraction of a cycle between the vibrations of two particles, measured in degrees or radians. The two particles must be vibrating at the same frequency.

Question 15

Phase difference equation.

Answer 15

Phase difference in radians = (2πd)/λ
Where d is the distance between particles and λ is the wavelength.