Waves Key Words

Question 1

Coherence

Answer 1

a wave that has a constant frequency and therefore a constant phase difference

Question 2

Standing wave

Answer 2

A wave where each position has its own maximum displacement, only the
antinode experience the maximum amplitude and the nodes have zero displacement. Energy
is not transferred along the wave.

Question 3

Progressive wave

Answer 3

• A wave where each particle will in turn oscillate with the maximum
  amplitude and energy is transferred along the direction of propagation.

Question 4

Longitudinal wave

Answer 4

A wave where oscillations are parallel to the direction of wave
propagation. There are areas of rarefaction and compression

Question 5

Transverse wave

Answer 5

– a wave where oscillations are perpendicular to the direction of wave
propagation

Question 6

Plane-polarised

Answer 6

Transverse waves are plane-polarised if the vibrations stay in one plane
only

Question 7

Unpolarised

Answer 7

If wave vibrations change from one plane to another they are unpolarised.

Question 8

Displacement

Answer 8

the displacement of a vibrating particles is its distance and direction from
the equilibrium position

Question 9

Amplitude

Answer 9

the maximum displacement of a wave from the equilibrium position

Question 10

Wavelength

Answer 10

The least distance between two adjacent vibrating particles with the same
displacement and velocity at the same time.

Question 11

Period of a wave

Answer 11

the time for one complete wave to pass a fixed point

Question 12

hertz

Answer 12

Unit of frequency = s-1

Question 13

Phase difference

Answer 13

phase difference between two vibrating particles at the same frequency
is the fraction of a cycle between the vibrations of the two particles.

Question 14

Phase difference

Answer 14

phase difference between two vibrating particles at the same frequency
is the fraction of a cycle between the vibrations of the two particles

Question 15

Refraction

Answer 15

when waves pass across a boundary the wave speed changes and the
wavelength change. If the wave crosses the boundary at an angle other than 90 degrees
then the direction of the wave also changes.

Question 16

Refractive index

Answer 16

the ratio of the speed of light in a vacuum over the speed of light in a
medium.

Question 17

Total internal reflection

Answer 17

The complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.