Physics A

Question 1

Amplitude

Answer 1

Height of a wave from its undisturbed position

Question 2

Wavelength

Answer 2

The distance between two crests or two troughs

Question 3

Frequency

Answer 3

Number of waves passing through a point each second

Question 4

Longitudinal

Answer 4

Oscillations are along the same direction as the direction of travel
eg sound waves

Question 5

Transverse

Answer 5

Oscillations are at right angles to the direction of travel
eg water waves, all EM waves

Question 6

Period

Answer 6

Time needed for one wave to pass a given point

Question 7

Compression

Answer 7

Region in a longitudinal wave where the particles are closest together.

Question 8

Rarefaction

Answer 8

Region in a longitudinal wave where the particles are furthest apart

Question 9

Absorb

Answer 9

When the energy of an EM wave is taken up by an object

Question 10

Transmit

Answer 10

When a wave is able to pass through a material

Question 11

Reflect

Answer 11

The wave bounces of a surface; the angle of incidence is equal to the angle of reflection

Question 12

Refract

Answer 12

The wave changes direction when it enters a medium of different density where it has a different speed

Question 13

Radio waves

Answer 13

Uses : television , radio
Why : reflected by ionosphere so can travel over long distances

Question 14

Microwaves

Answer 14

Uses : satellite communications cooking food
Why : able to pass through atmosphere to satellites
Has heating effect

Question 15

Infrared

Answer 15

Uses : cooking food, electrical heaters infrared cameras.
Why : has a heating effect, is emitted by objects so can be detected

Question 16

Visible light

Answer 16

Uses : fibre optic communications
Why : able to pass along a cable by total internal reflection

Question 17

Ultra violet

Answer 17

Uses : sun tanning , energy efficient lamps
Why : increases amount of melanin (brown pigment) in skin
Risk : premature skin ageing , increase risk of skin cancer (some can ionise)

Question 18

X-rays

Answer 18

Uses : medical imaging, treatments
Why : absorbed by bone but transmitted through soft tissue
Risk : ionising can cause skin mutation of genes, cancer

Question 19

Gamma rays

Answer 19

Uses : medical imaging, treatments
Why : able to be passed out the icy and detected by gamma cameras, can kill cancerous cells
Risk : Ionising - can cause mutation of genes and cancer

Question 20

Ionising

Answer 20

High energy radiation which can remove electrons leaving ions. If this happens in DNA it can cause a mutation that could lead to cancer.

Question 21

EM spectrum

Answer 21

The collective name for all types of EM radiation. They are all transverse waves that all travel at 300,000,000 m/s

Question 22

Production

Answer 22

Gamma rays are produce from the decay of an unstable nucleus
Radio waves are produced by oscillations in electrical circuits