Light

Question 1

Light

Answer 1

the natural agent that stimulates sight and makes things visible.

Question 2

Beam

Answer 2

a ray or shaft of light.

Question 3

Ray

Answer 3

each of the lines in which light (and heat) may seem to stream from the sun or any luminous body, or pass through a small opening.

Question 4

Energy

Answer 4

the property of matter and radiation which is manifest as a capacity to perform work (such as causing motion or the interaction of molecules).

Question 5

Luminous

Answer 5

relating to light as it is perceived by the eye, rather than in terms of its actual energy.

Question 6

Non-Luminous

Answer 6

Not capable of producing light, but can be capable of reflecting light from another source.

Question 7

Speed of Light

Answer 7

The distance light can travel in a unit of time through a given substance. Light travels at about 186,000 miles, or 300,000 kilometers, per second.

Question 8

Shadow

Answer 8

a dark area or shape produced by a body coming between rays of light and a surface.

Question 9

Electromagnetic Spectrum

Answer 9

complete range of wavelengths of energy radiated as electric and magnetic fields

Question 10

Radio Waves

Answer 10

low energy electromagnetic waves with a much lower frequency and longer wavelength than visible light

Question 11

Infra-red Radiation

Answer 11

invisible radiation emitted by all warm objects. You feel infra-red radiation as heat.

Question 12

Visible Light

Answer 12

very small part of the electromagnetic spectrum to which our eyes are sensitive

Question 13

Ultraviolet Radiation

Answer 13

invisible radiation similar to light but with a slightly higher frequency and more energy

Question 14

X-Rays

Answer 14

high-energy electromagnetic waves that can be transmitted through solids and provide information about their structure

Question 15

Gamma Rays

Answer 15

high-energy electromagnetic radiation produced during nuclear reactions. They have no mass and travel at the speed of light.

Question 16

Electromagnetic Waves

Answer 16

electromagnetic energy that is transmitted as moving electric and magnetic fields. There are many different types of electromagnetic energy, e.g. light, microwaves, radio waves.

Question 17

Reflection

Answer 17

bouncing off the surface of a substance

Question 18

Scattering

Answer 18

describes light sent in many directions by small particles within a substance

Question 19

Transparent

Answer 19

describes a substance that allows most light to pass through it. Objects can be seen clearly through transparent substances.

Question 20

Translucent

Answer 20

allowing light to come through imperfectly, as in frosted glass

Question 21

Opaque

Answer 21

describes a substance that does not allow any light to pass through it

Question 22

Concave

Answer 22

curved inwards

Question 23

Convex

Answer 23

curved outwards

Question 24

Lateral Inversion

Answer 24

reversed sideways

Question 25

Refraction

Answer 25

change in the speed of light as it passes from one substance into another. It usually involves a change in direction.

Question 26

Photons

Answer 26

a particle such as a quantum of light or electromagnetism

Question 27

Pupil

Answer 27

Allows light into the eye. When there is dim light, our pupil becomes bigger. When there is bright light, our pupil becomes smaller.

Question 28

Iris

Answer 28

Controls the size of the pupil and controls how much light is let in. When there is dim light, our pupil becomes bigger. When there is bright light, our pupil becomes smaller.

Question 29

Lens

Answer 29

Focuses light onto the retina, it is transparent. There are no blood vessels.

Question 30

Retina

Answer 30

Detects light using cells called photoreceptors

Question 31

Optic Nerve

Answer 31

Receives signals from the retina and sends them to the brain

Question 32

Sclera

Answer 32

Protects the eye and helps it maintain its shape

Question 33

Choroid

Answer 33

Contains blood vessels, which bring nutrients to the eye

Question 34

Cornea

Answer 34

Protects the front of the eye, there are no blood vessels.

Question 35

Vitreous humour

Answer 35

Helps the eye maintain its shape

Question 36

Aqueous humour

Answer 36

Brings nutrients to the cornea and lens, which lack blood vessels