Unit 11 -Waves 1

Question 1

What is a progressive wave?

Answer 1

A means of transferring energy from one place to another without a transfer of matter between the two points.

Question 2

What is the characteristics of a transverse wave?

Answer 2

The direction of oscillation of a wave is perpendicular to the direction of motion of the wave.

Question 3

What is the characteristics of a longitudinal wave?

Answer 3

The direction of oscillation of a wave is parallel to the direction of motion of the wave.

Question 4

What are examples of transverse waves?

Answer 4

All EM waves are transverse (e.g. radio waves,microwaves etc.)

Question 5

What are examples of longitudinal waves?

Answer 5

Sound waves and p-waves

Question 6

What is the definition of displacement?

Answer 6

Distance from the equilibrium position in a particular direction.

Question 7

What does amplitude mean?

Answer 7

Maximum displacement from the equilibrium position

Question 8

What is meant by wavelength?

Answer 8

Minimum distance between two points in phase on adjacent waves.

Question 9

What is a period?

Answer 9

Time taken for one oscillation to pass a given point.

Question 10

What is frequency?

Answer 10

Number of wavelengths passing a given point per unit time.

Question 11

What is waves speed?

Answer 11

Distance travelled by the wave per unit time

Question 12

What is phase difference?

Answer 12

It describes the difference between the displacements of the particles along a wave, or the difference between the displacements of the particles on different waves.

Question 13

What does reflection mean?

Answer 13

When a wave changes direction at a boundary between two different media, remaining in the original medium.

Question 14

When does refraction occur?

Answer 14

when a wave changes direction as it changes speed when it passes from one medium to another

Question 15

What happens when a ray enters a dense medium?

Answer 15

Speed decreases
refraction ray goes towards the normal

Question 16

What happens when a ray enters a less dense medium?

Answer 16

Speed increases
refraction ray goes away from the normal

Question 17

What is diffraction?

Answer 17

The spreading out of a wave as it passes through an gap/aperture or when they encounter an obstacle

Question 18

What is polarisation?

Answer 18

The particles oscillate along one direction only, which means that the wave is confined to a single plane.

Question 19

What does intensity mean?

Answer 19

The radiant power passing through a surface per unit area measured in Wm-2.

Question 20

Why do X-rays and gamma rays overlap?

Answer 20

Waves not classified by wavelength but by origin, X-rays are emitted by fast-moving electrons, whereas gamma rays come from unstable atomic nuclei

Question 21

What is the critical angle?

Answer 21

The angle of incidence at the boundary between two media that will produce and angle of refraction of 90°

Question 22

What is superposition?

Answer 22

When two waves of the same type cross at the same point in time and space. It is defined as “the vector sum of the two displacements”