Waves

Question 1

How do you calculate period ?

Answer 1

1/frequency

The time it takes for one full oscillation

Measured in seconds

Question 2

What are transverse waves ?

Answer 2

Waves that have oscillations which are perpendicular to the direction of energy transfer . These include

All electromagnetic waves
Ripples in water
A wave on a string

Question 3

What is a longitudinal wave ?

Answer 3

Wave which has ocissilations that are parallel to the energy transfer .

Question 4

What is the wave speed?

Answer 4

Speed at which energy is being transferred .

Question 5

What is the wave speed equation ?

Answer 5

Frequency x wave length

Question 6

What is the amplitude of the wave ?

Answer 6

Maximum displacement on the wave from it’s undisturbed position

Measured in m

Question 7

What is the frequency ?

Answer 7

The number of complete waves per second passing through a certain point

Question 8

What is the law of reflection ?

Answer 8

Angle of incidence = angle of reflection when measured to the normal

Question 9

What is the angle of incidence ?

Answer 9

The angle between the incoming wave and the normal wave

Question 10

What is the angle of reflection ?

Answer 10

The angle between the reflected wave and the normal

Question 11

What is the normal?

Answer 11

An imaginary line that is the perpendicular to the surface at the point of incidence

Question 12

What is specular reflection ?

Answer 12

When a wave is reflected in a single direction by a smooth surface .

Like reflections from a mirror

Question 13

What is diffuse reflection ?

Answer 13

When a wave is reflected by the rough surface . The rays are scattered in different directions

Like a piece of paper

Question 14

Order of EM WAVES from shortest to longest wave length

Answer 14

Radio waves      Shortest wave length 
Micro waves 
Infrared waves
Visible light 
Ultra violet rays 
X rays                Longest wave length 
Gamma rays

Question 15

Why is there a variety of frequencies between EM waves?

Answer 15

Variation in changes of the nucleus of atoms

Question 16

What is refraction ?

Answer 16

When a wave crosses a boundary between materials at an angle it will change direction , the wave length will change but the frequency will stay the same

Question 17

What does refraction depend on?

Answer 17

How much the waves slows down when hitting the material.

Question 18

Define optical density?

Answer 18

A measure of how quickly light can travel through an object

Question 19

What are EM waves made out of ?

Answer 19

Oscillating electric and magnetic fields

Question 20

What are microwaves used for ?

Answer 20

In satellites
For communication to and from satellites microwaves must be used . However they must be able to move through the earths watery atmosphere

Also they can be used for cooking food . In microwave ovens these waves need to be absorbed by water molecules so they use different wave lengths

Question 21

Uses of infrared rays?

Answer 21

Can be used to monitor temperatures.

Can be used in thermal cameras to pick up hotspots .

Can be used in electrical heaters . They contain a wire which when heated emits infrared radiation . This energy is then transferred into thermal energy stores

Question 22

Uses of ultraviolet rays ?

Answer 22

Can be used in tanning salons

Can be used in ink . When lighted up the ink will become visible

Question 23

How is visible light used in fibre optic cables?

Answer 23

Long strings of data can be carried over by pulses of visible light

Thy work because the light rays are reflected of the glass bouncing back and forth

Question 24

Uses or x rays and gamma rays ?

Answer 24

X rays can be used to detect damage to bones

Gamma radiation can be used as a medical tracer

Radiographers use both rays to kill cancer cells

Question 25

Dangers of EM waves?

Answer 25

UV waves can cause damage to skin cells. Can increase the risk of cancer

X rays and gamma rays are ionizing radiation which can cause mutations in cells which could lead to cell destruction .

Question 26

What is black body radiation ?

Answer 26

A black body is an object that absorbs all of the radiation that hits it . No radiation is reflected or transmitted

Question 27

How does radiation effect the earths temperature ?

Answer 27

Temperature depends on the amount of radiation it reflects , absorbs or emits

Question 28

How do x rays scan breaks in bones ?

Answer 28

X rays pass easily through materials like flesh but struggle passing through denser materials like bone . So its the amount of radiation that is absorbed that gives you an X ray image

Question 29

How do colour filters work?

Answer 29

Filter out different wave lengths so that only certain colours are absorbed .

Question 30

Which of these is an example of a longitudinal wave?

Ripples on the surface of water
Sound waves
X rays

Answer 30

Sound waves