1. Waves

Question 1

What do all waves transfer?

Answer 1

Energy

Question 2

What is frequency (f)?

Answer 2

Frequency is the number of waves produced per second

Question 3

What is the frequency equation?

Answer 3

f =N/t (number of waves over time)

Question 4

What is a wavelength (λ)?

Answer 4

The distance from one point of a wave to the same point on the next wave

Question 5

What is the amplitude of a wave?

Answer 5

The distance from a waves mid point, to its crest or trough

Question 6

What is a period (T)?

Answer 6

A period is the time between each wave (related to frequency)

The time it takes for a wavelength to pass a point

Question 7

What is the period equation?

Answer 7

T = 1/f (number one over frequency

Question 8

What is a transverse wave? Give examples

Answer 8

A wave which travels at a right angles to the direction of its origin (up and down)

E.g. X-ray, water

Question 9

What is a longitudinal wave? Give examples

Answer 9

A wave which travels in the direction of its origin (side to side)

E.g. Sound

Question 10

What is the equation which can be used to determine the time it takes for a wave to travel a certain distance?

Answer 10

v = fλ (frequency times wavelength)

or

v = d/t (speed, distance, time equation)

Question 11

What is the range of human hearing?

Answer 11

20 Hertz (Hz) to 20 000 Hertz

Question 12

What are sounds above the range of human hearing called?

Answer 12

Ultrasounds

Question 13

What happens when waves hit a barrier?

Answer 13

When waves hit a barrier they diffract, spreading out around the back of the barrier

Question 14

Higher frequencies diffract better than lower frequencies

True of False?

Answer 14

False - they diffract less well than lower frequencies

Question 15

What speed do electromagnetic spectrum waves travel at?

Answer 15

3x10^8 m/s

Question 16

What is the order of the electromagnetic spectrum, from shortest to longest?

Answer 16

Gamma rays, X-rays, Ultraviolet rays, Visible light, Infra-red, Microwaves, TV/Radio waves

(Good Xylophones Usually Vibrate Intensely Meanwhile Tambourines Rattle)

Question 17

If Gamma rays have a high frequency then is their wavelength likely to be short or long?

Answer 17

Short, and they carry the most energy

Question 18

When light waves move from one material to another, what change will it undergo? And what will the ray bend towards?

Answer 18

A change in direction

It will bend towards the normal

Expansion - This means that when light moves to a more optically dense material, the speed of light slows, and the wavelength shortens

Question 19

What are the light rays going into, and leaving a glass block called?
And what are the angles between these rays and the glass block called?

Answer 19

The incident ray (going in) and the refracted ray (coming out)

Angle of incidence and the angle of refraction

Question 20

Which type of light enters a glass prism, and what type of light is it refracted into?

Answer 20

When monochromatic light (white light) refracts in a glass prism, it splits up, revealing the colours of the visible portion of the electromagnetic spectrum (the rainbow)

Question 21

What is a critical angle?

Answer 21

The point at which the ray of light stops refracting, and total internal reflection occurs

Question 22

What occurs when the angle of refraction is so large the refracted ray does not leave the material?

Answer 22

Total Internal reflection

Question 23

Total internal reflection is a useful property of light, why is this?

Answer 23

It can be used to allow light to travel down a fibre optic cable

Question 24

What does a convex lens look like, and what does it do to light? Give examples

Answer 24

Convex lenses look like this: ()

They converge light to a single point called the focal point

E.g. cameras

Question 25

What does a concave lens look like, and what does it do to light? Give examples

Answer 25

Concave lenses look like this: )(

They spread light out, meaning the focal point is actually being the lens

E.g. “spy holes” in doors

Question 26

The focal length is measured between the lens and the focal point

True or False?

Answer 26

True

Question 27

Which lens would a person with long sightedness use?

Answer 27

This means the person cannot focus things near to them, so we want to bring the focal point forward

Therefore we would use a convex lens

Question 28

Which lens would a person with short sightedness use?

Answer 28

This means the person cannot focus on things far away, so we want to push the focal point back

Therefore we would use a concave lens