04 Waves Basics and EM Spectrum - 3rd Form

Question 1

What is the use of UV radiation?

Answer 1

produced by tanning bed lights to tan skin

used to detect conterfeit money

Question 2

Give three properties (features) common to all EM waves

Answer 2

They all…

travel at the speed of light

all transverse waves

all travel through a vacuum

all transfer energy and information without transferring matter

Question 3

Which wave has the largest wavelength?

Answer 3

wave 1

largest distance between adjacent crests

Question 4

List the EM spectrum in order of decreasing frequency

Answer 4

Gamma

X-ray

UV

Visible

IR

Microwave

Radio

Question 5

How is wavespeed, wavelength and frequency related?

Answer 5

wavespeed = wavelength x frequency

Question 6

Label the compressions, rarefactions and wavelength on the longitudinal wave below

Answer 6

Question 7

What is 204 nm in m?

Answer 7

204 x 10^-9 m

Question 8

How can you make a longitudinal wave with a slinky?

Answer 8

move your hand in a forwards and backwards movement

Question 9

How would you measure the frequency of waves passing a jetty?

Answer 9

Time how long it take for 10 waves to pass the end of the jetty

frequency = 10 waves / time for 10 waves to pass

Question 10

Fred noticed that 10 waves passed a point in 5 seconds. What is the frequency of the wave?

Answer 10

frequency = 10 waves/ 5 s

= 2 Hz

Question 11

What is 700 micrometres in metres?

Answer 11

700 x 10^-6 m

Question 12

Fred noticed that 10 waves passed a point in 5 seconds. What is the period of the wave?

Answer 12

Time period = 5 seconds / 10 waves

= 0.5 seconds for one wave to pass

Question 13

Which wave has the largest amplitude?

Answer 13

wave 2

It has the largest displacement from the equilibrium

Question 14

What is the unit for time period?

Answer 14

seconds or s

Question 15

What is the unit for amplitude?

Answer 15

metres (m) or decibels(dB)

Question 16

Define wavefront

Answer 16

A line joining points on a wave at the same point in their wave cycle

Question 17

Why are UV waves dangerous?

Answer 17

They can damage the retina and damage eye sight

They can cause damage to surface cells and may cause skin cancer

Question 18

What is the use of microwaves?

Answer 18

produced by microwaves to cook food

produced by mobile phones to communicate

Produced by satellites to send signals to satellite dishes

Question 19

What is a transverse wave?

Answer 19

Where the oscillations are perpendicular to the direction of energy travel

Question 20

How do the waves of red light differ from waves of violet light

Answer 20

ROY G BIV

Red light-larger wavelength and lower frequency- it has less energy

Blue light- smaller wavlength and higher frequency- it has more energy

Question 21

What are the uses of infrared radiation (IR)

Answer 21

emitted by ovens to cook food

emitted by radiators to heat houses

emitted by tv controllers to control t.v.

Question 22

What is the relationship between wavelength and frequency of a wave?

Answer 22

As wavelength increases, frequency decreases

They are inversely proportional

Question 23

What is the use of X-rays?

Answer 23

Used to detect breaks in bones

used to detect crystal structure in salts

Question 24

List the EM spectrum in order of increasing frequency

Answer 24

Radio

Microwave

IR

Visible

UV

X-ray

Gamma

Question 25

What is 13 kHz in Hz?

Answer 25

13 x 10³ Hz

Question 26

What is the relationship between time period and frequency?

Answer 26

time period = 1 / frequency or frequency = 1 / time period

Question 27

How is gamma radiation dangerous?

Answer 27

It can cause mutations in cells- cancer

Question 28

How are X-rays dangerous?

Answer 28

They can cause mutations of cells- cancer

Question 29

Which parts of the EM spectrum is considered to be dangerous?

Answer 29

UV X-ray Gamma

Question 30

Label the wavelength, amplitude, crest and trough of the transverse wave below

Answer 30

Question 31

How is infrared dangerous?

Answer 31

It can cause skin burns if too hot

Question 32

What is a longitudinal wave?

Answer 32

Where the oscillations are **parallel** to the direction of energy travel

Question 33

Give three examples of a longitudinal wave

Answer 33

sound shock wave Seismic P wave

Question 34

What are the uses of radio waves?

Answer 34

radio signal for radio radar walkie talkie signals t.v. signals

Question 35

What are the uses of gamma radiation?

Answer 35

Used to kill cancer tumours used to sterilise medical equipment emitted by radioisotope tracers to detect cancer in the body

Question 36

How do you calculate the frequency of a water wave?

Answer 36

frequency = number of waves/ time for those waves to pass a point

Question 37

What does monochromatic mean?

Answer 37

Light of a single wavelength or colour.

Question 38

What is 100 MHz in Hz?

Answer 38

100 x 10⁶ Hz

Question 39

What is the unit for wavelength?

Answer 39

metre or m

Question 40

Give three examples of a transverse wave

Answer 40

water wave radio, microwave, IR, UV, X ray, Gamma Seismic S wave

Question 41

Define wavelength

Answer 41

The distance between a point on one wave and the same point on the next wave.

Question 42

Which wave has the highest frequency?

Answer 42

wave 3 ## Footnote *it has more waves per second*

Question 43

How are all the EM radiation different?

Answer 43

They have.... different wavelengths different frequencies therefore they have different uses and dangers

Question 44

What is the unit for wavespeed?

Answer 44

metre per second or m/s

Question 45

What is the use of visible light?

Answer 45

produced by light bulbs to see things produced by bioluminescent creature to attract prey

Question 46

What is the unit for frequency?

Answer 46

Hertz or Hz

Question 47

What type of wave is sound?

Answer 47

Longitudinal vibrations are parallel to direction of energy travel

Question 48

Define frequency

Answer 48

number of waves *passing a point* per unit time

Question 49

Define amplitude

Answer 49

The **maximum** displacement of a wave from its equilibrium position.

Question 50

Define Time Period

Answer 50

the time for one complete wave *to pass a point*