Topic 5 - Light and the EM spectrum

Question 1

Angle of incidence=

Answer 1

Angle of reflection

Question 2

Total internal refelction occurs when

Answer 2

The wave is travelling through a dense material into a less dense material. When the angle of incidence is larger than the critical angle.

Question 3

Specular reflection

Answer 3

When waves are reflected in a single direction by a smooth surface.

Question 4

Diffuse reflection

Answer 4

When waves are reflected in all directions by a rough surface because the normal is different for each incident ray

Question 5

All different colours of light have

Answer 5

Different wavelengths

Question 6

Opaque objects

Answer 6

Dont transmit light

Question 7

White objects

Answer 7

Reflects all wavelengths of light equally

Question 8

Black objects

Answer 8

Absorb all wavelengths of light

Question 9

Transparent and translucent objects

Answer 9

Transmit light

Question 10

Coverging lenses

Answer 10

Bulge outwards in the middle and causes rays of light to converge together at the principal focus

Question 11

Diverging lenses

Answer 11

A diverging lens caves inwards and causes rays of light to spread out

Question 12

Principal focus on converging lenses

Answer 12

Where the rays meet after being refracted through the lens

Question 13

Principal focus on diverging lens

Answer 13

Where the rays meet if thye get traced backwards through the lens. It is before the lens.

Question 14

Focal length

Answer 14

The distance from the centre of th lens to the principal focus

Question 15

A real image is

Answer 15

When the light rays actually come together to form the image.

Question 16

A virtual image is

Answer 16

when light rays from the object appear to be coming from a different place to where they are coming from.

Question 17

Real images are usually created by

Answer 17

Converging lenses

Question 18

Virtual images are usually created by

Answer 18

Diverging/convex lenses

Question 19

Electromagnetic waves are

Answer 19

Transverse

Question 20

EM waves travel at

Answer 20

the same speed through a vacuum, but have different speeds in different materials.

Question 21

All EM waves transfer energy from

Answer 21

A source to an absorber

Question 22

Example of source to absorber in EM waves

Answer 22

When near an electric heater, infrared waves transfer energy from the heaters thermal energy store to your thermal energy store

Question 23

Types of EM waves in order of wavelength

Answer 23

Radio waves
Microwaves
Infrared
Visible light
Ultra Violet
X-Rays
Gamma Rays

Question 24

The EM spectrum is in order of

Answer 24

Decreasing wavelength and increasing frequency

Question 25

The higher the frequency of an EM wave

Answer 25

The more energy is transfers (so it is more dangerous for humans)

Question 26

EM waves at a boundary can

Answer 26

Be absorbed, reflected, refracted, or transmitted

Question 27

Radio waves are ... through the body

Answer 27

transmitted

Question 28

Some wavelengths of microwaves can be.... by bodily cells

Answer 28

Absorbed

Question 29

Infrared and visible light are mostly ....or.... by the skin

Answer 29

Reflected or absorbed

Question 30

Ultraviolet is ... by the skin and is slightly .....

Answer 30

Absorbed, ionising

Question 31

Colours of visible light in order of decreasing wavelength

Answer 31

Red Orange Yellow Green Blue Indigo Violet

Question 32

All bodies and objects constantly

Answer 32

Absorb and emit EM waves

Question 33

The intensity and distribution of the wavelengths of EM emission depend only on

Answer 33

Temperature

Question 33

For an object to be at a constant temp

Answer 33

It needs to radiate the same avergae power as it absorbs

Question 34

Radiation effects the earths temperature by

Answer 34

Absorbing during the day fro mthe sun, and emitting from the atmosphere during the night

Question 35

Steps of core practical investigating how surfaces emit radiation

Answer 35

Use 4 test tubes wrapped in the same material but with different surfaces Add boiling water and measure how quickly temperature decreases using a thermometer

Question 36

Microwaves can lead to

Answer 36

Internal heating of humans

Question 37

Infrared can lead to

Answer 37

Skin burns

Question 38

Ultraviolet can lead to

Answer 38

damage to surface cells such as skin and eyes, which leads to skin cancer and eye conditions

Question 39

X-rays and gamma can lead to

Answer 39

Mutation or damage to deeper tissues

Question 40

Radio waves are used in

Answer 40

Broadcasting Communications Satellite transmissions

Question 41

Microwaves are used in

Answer 41

Cooking Communications Satellite transmissions

Question 42

Infrared is used in

Answer 42

Cooking Thermal imaging Short-range communications Optical fibres TV remotes Security systems

Question 43

Visible light is used for

Answer 43

Vision Photography Illumination

Question 44

Ultraviolet is used for

Answer 44

Security marking Flourescent objects and lights Detecting forged bank notes Disinfecting water

Question 45

X-rays are used for

Answer 45

Observing the internal structure of objects Medical x-rays Airport security scanners

Question 46

Gamma rays

Answer 46

Sterilising medical equipment and food Detection fo cancer Cancer treatment

Question 47

Radio waves can be produced by or induce

Answer 47

Oscillations in electrical circuits from a transmitter or at a receiver

Question 48

Changes in atoms and nuclei can lead to or be caused by

Answer 48

Can lead to radiation being generated over a wide frequency range Can be caused by absorbtion of different radiations Changes in the nucelus itself leads to the production of gamma rays