Waves

Question 1

What do waves transfer?

Answer 1

energy and information

Question 2

What is frequency?

Answer 2

the number of waves passing through a point per second (Hz)

Question 3

Define wavelength

Answer 3

the distance between two adjacent peaks on a wave

Question 4

Define amplitude

Answer 4

The maximum displacement of the wave from its equilibrium position

Question 5

What is the period of the wave?

Answer 5

the length of time it takes for one full wave to pass through a point

Question 6

How do you calculate the wave speed?

Answer 6

wavelength * frequency

Question 7

State an equation linking frequency and period of a wave

Answer 7

Frequency = 1 / Time Period

Question 8

What is a longitudinal wave?

Answer 8

Vibrations are parallel to the direction of energy transfer

Question 9

What is a transverse wave?

Answer 9

a wave with oscillations that are perpendicular (90 degrees) to the direction of energy transfer

Question 10

Explain the “doppler effect”

Answer 10

When a wave source is moving towards the observer: the observed frequency increasing and the observed wavelength decreases
When a wave source is moving away from the observer: observed frequency decreases and observed wavelength decreases (WAVE SPEED = WAVELENGTH * FREQUENCY)

Question 11

What type of waves are electromagnetic waves?

Answer 11

transverse

Question 12

What are the 7 electromagnetic waves?

Answer 12

radio, microwaves, infra-red, visable light, ultraviolet, xrays, gamma rays

Question 13

What are the uses of radio waves?

Answer 13

communications, satellite transmissions

Question 14

What are microwaves used for?

Answer 14

cooking in microwave ovens, satellies, communications

Question 15

What are infrared used for?

Answer 15

cooking, thermal imaging, telivision remote controls

Question 16

What are uses of visable light?

Answer 16

SIGHT, photography, optical fibres

Question 17

What is the use of ultraviolet rays?

Answer 17

security marking and flourescent lamps

Question 18

What are some uses of xrays?

Answer 18

scanners, medical imaging

Question 19

What are the uses of gamma rays?

Answer 19

Used to sterilise food, medical equiptment, cancer diagnosis

Question 20

What are the risks of gamma rays?

Answer 20

can cause mutations or damage to body cells

Question 21

What are the disadvantages of microwaves?

Answer 21

can cause heating of internal tissues in the body

Question 22

What is the disadvantage of infrared radiation?

Answer 22

it can cause skin burns

Question 23

What is the disadvantage of ultraviolet?

Answer 23

it can cause skin cancer or eye conditions

Question 24

What is the normal?

Answer 24

a line perpendicular to the boundary

Question 25

What happens when light is reflected?

Answer 25

it is reflected off a flat surface - the angle of incidence is the same as the angle of reflection

Question 26

What happens when light is refracted?

Answer 26

the light changes speed and direction

• if it is more dense, the light will travel slower and bend towards the normal
• if it is less dense, the light will travel faster and bend away from the normal