3.1 General Wave Properties

Question 1

What is a wave?

Answer 1

A regular disturbance transferring energy in the direction of the wave’s propagation without transferring matter.

Question 2

What is a transverse wave?

Answer 2

A wave in which oscillations are at right angles (perpendicular) to the direction of motion.

Question 3

Give examples of transverse waves

Answer 3

Waves on a string, all electromagnetic waves (eg. visible light), ripples on water, vibrations on guitar strings

Question 4

What is a longitudinal wave?

Answer 4

A wave where the oscillations are parallel to (in the same direction as) the direction of motion.

Question 5

Give examples of longitudinal waves

Answer 5

Pulses along a spring, sound waves, ultrasound

Question 6

Transverse waveforms have…

Answer 6

Peaks and troughs

Question 7

Longitudinal waveforms have…

Answer 7

Compressions (particles pushed together) and rarefactions (particles moved apart)

Question 8

Wavelength is…

Answer 8

the distance between a point on one wave and the same point on the next wave (eg. Peak to peak)
measured in metres (m)

Question 9

Displacement is…

Answer 9

• The distance from equilibrium position
• At maximum distance (peaks or troughs), this is the amplitude (the maximum displacement of the wave)

Question 10

Frequency is…
+ its equation

Answer 10

-The number of complete waves passing a given point per second, or the number of waves per second produced by the source.
-Measured in Hertz (Hz)
-Freq = 1 / time in seconds

Question 11

State the wave equation for wavespeed

Answer 11

v = λ x f
• v = velocity (m/s)
• λ = wavelength (m)
• f = frequency (Hz)

Question 12

What is refraction?

Answer 12

Refraction is the change in speed of a wave when crossing a boundary between two media, resulting in a change in direction.

Question 13

Which property of a wave is not changed by refraction?

Answer 13

The frequency.

Question 14

What happens when waves are incident on a flat surface?
.

Answer 14

Reflection

Question 15

A stronger reflected wave is produced when…

Answer 15

The surface is smoother.

Question 16

Why do rough surfaces appear matt when illuminated?

Answer 16

The reflected rays light are scattered in all directions.

Question 17

When entering a denser material, light waves…

Answer 17

..slow down and bend towards the normal.

Question 18

When entering a less dense material, light waves…

Answer 18

…speed up and bend away from the normal.

Question 19

What is diffraction?

Answer 19

The spreading out of waves passing through a narrow gap or across an edge.

Question 20

What size of gap produces the largest diffraction?

Answer 20

A gap of the same width as the wavelength of the wave passing through it.

Question 21

What is a ripple tank?

Answer 21

A shallow glass tank with an oscillating paddle/needle to create waves. It is illuminated from above so waves can be seen on the surface below the tank.

Question 22

Describe how to demonstrate reflection using a ripple tank.

Answer 22

Waves will reflect off the glass sides of the tank.

Question 23

Describe how to demonstrate refraction using a ripple tank.

Answer 23

Place a glass box across half of the floor of the ripple tank. The waves will change speed when travelling through the less dense area.