Waves (Paper 2)

Question 1

Define oscillation

Answer 1

Forwards and backwards movement about a central point

Question 2

Define propagate

Answer 2

Direction of movement

Question 3

What are the properties of transverse waves?

Answer 3

• waves oscillate perpendicular to the direction of motion
• does not require a medium to travel through
• eg light or EM waves

Question 4

What are the properties of longitudinal waves?

Answer 4

• waves oscillate parallel to the direction of motion
• requires a medium to travel through
• eg sound or water

Question 5

In terms of longitudinal waves, define compressions and rarefactions

Answer 5

The points in the wave where the particles are closer together and rarefactions are where the particles are further apart

Question 6

What is the equation for period?

Answer 6

1 / frequency

Question 7

What is the equation for wave speed?

Answer 7

frequency x wavelength

Question 8

What is the electromagnetic spectrum (largest to smallest)?

Answer 8

Radio waves, micro waves, infrared, visible light, ultra violet, x-rays, gamma rays

Question 9

Are seismic waves transverse or longitudinal and how are they produced?

Answer 9

Transverse and they are produced by earthquakes

Question 10

Are p-waves transverse or longitudinal?

Answer 10

longitudinal

Question 11

Why do all objects absorb and emit infrared radiation?

Answer 11

The energy of the infrared waves matches the energy produced by particles vibrating

Question 12

What is the law of reflection?

Answer 12

Angle of incidence = angle of reflection

Question 13

What properties do the best emitters have?

Answer 13

dark, matte surfaces

Question 14

What properties do the worst emitters have?

Answer 14

light, shiny surfaces

Question 15

Define black body radiators

Answer 15

objects that absorb all radiation incident on it, no radiation is transmitted or reflected

Question 16

What is the speed of light?

Answer 16

3 x (10 to the 8) m/s

Question 17

Define specular reflection

Answer 17

When light reflects perfectly off of a smooth surface, usually giving mirror images

Question 18

Define diffuse reflection

Answer 18

When light reflects off of a rough surface and the light doesn’t reflect perfectly, giving distorted images

Question 19

Which lights do yellow pigments reflect?

Answer 19

Red and green lights

Question 20

Which lights do magenta pigments reflect?

Answer 20

Blue and red lights

Question 21

Which lights do cyan pigments reflect?

Answer 21

Blue and green lights

Question 22

Define refraction

Answer 22

the change in direction of waves when they travel across a boundary

Question 23

In refraction, when does the light bend towards the normal?

Answer 23

When the wave speed decreases and the light crosses the boundary into a thicker medium

Question 24

In refraction, when does the light bend away from the normal?

Answer 24

When the wave speed increases and the light crosses the boundary into a thinner medium

Question 25

When a light ray travels from glass to air, what happens to the angles of refraction and incidence?

Answer 25

the angle of refraction is bigger than the angle of incidence

Question 26

When a light ray travels from air to glass, what happens to the angles of refraction and incidence?

Answer 26

the angle of refraction is smaller than the angle of incidence

Question 27

Define focal length

Answer 27

The distance between the lens and the focal point

Question 28

What rays do convex lenses have?

Answer 28

Converging rays

Question 29

What rays do concave lenses have?

Answer 29

Diverging rays

Question 30

What is the difference between convex and concave lenses?

Answer 30

Concave are drawn like )( but convex are drawn like ()

Question 31

What are the 3 laws for drawing rays on diagrams with convex lenses?

Answer 31

1 - a ray hitting the centre of a lens will pass through in a straight line 2 - rays parallel to the principal axis will pass through the focal point on the other side of the lens 3 - rays passing through the focus before the lens will emerge parallel to the principal axis