Section 18 - Waves and the electromagnetic spectrum - Waves, boundaries and refraction

Question 1

What happens when a wave travels through a medium?

Answer 1

The particles of the medium vibrate and transfer energy and information between each other

Question 2

What is amplitude of a wave?

Answer 2

Displacement from rest position to a crest or trough

Question 3

What is the wavelength of a wave?

Answer 3

Length of a full cycle of wave, e.g. from crest to crest

Question 4

What is frequency?

Answer 4

The number of complete cycles of a wave passing a certain point per second. Measured in Hz

Question 5

What is period and equation for it?

Answer 5

The number of seconds it takes for one full cycle

Period = 1 ÷ frequency

Question 6

What are vibrations like in transverse waves?

Answer 6

Vibrations are perpendicular to the direction the wave travels.

Question 7

3 examples of transverse waves?

Answer 7

All electromagnetic waves, S-waves (type of seismic wave) and ripples/waves in water

Question 8

What are vibrations like in longitudinal waves?

Answer 8

Vibrations are parallel to the direction the wave travels

Question 9

2 examples of longitudinal waves?

Answer 9

Sound waves and P-waves (type of seismic wave)

Question 10

2 equations for wave speed?

Answer 10

Wave speed (m/s) = Distance (m) ÷ time (s)
v = x ÷ t
Wave speed (m/s) = Frequency (Hz) x Wavelength (m)
v = f x λ

Question 11

Three ways to measure speed of sound, water ripples and waves in solids?

Answer 11

Sound - use oscilloscope and two microphones distanced
Water ripples - Use strobe light to project ripples on screen
Waves in solids - Use peak frequency by hitting metal rod with hammer and microphone at other end

Question 12

3 things that can happen to waves when they meet a boundary?

Answer 12

Absorbed, transmitted or reflected

Question 13

What do waves transfer?

Answer 13

Energy from one place to another without transferring any matter

Question 14

Which EM wave wavelength type bends more through a boundary?

Answer 14

Shorter wavelengths bend more (e.g. blue light or UV)

Question 15

What happens when a wave crosses from less dense material to a denser material at an angle?

Answer 15

Refracts and slows down

Question 16

What is the angle of incidence?

Answer 16

The angle between the incoming ray and normal

Question 17

What is the angle of refraction?

Answer 17

The angle between the refracted ray and the normal