Light

2

Light is a form of energyCrooke’s Radiometer proves light has energy

Turns in sunlight as the light heats the black side

3

Shadows Light travels in a straight line.

If something gets in its path the light is blocked.

A shadow is formed.

4

Eclipses

Proves light travels in straight lines

5

Light travels in straight lines

6

Light on cards goes through if the cards are lined up. This also proves light travels in straight lines

7

Reflection

Incident ray

Normal

Reflected ray

Angle of incidence

Angle of reflection

Flat Mirror

Angle of incidence = Angle of reflection

8

Image Here in a plane mirror an

image is formed by the eye Can not appear on a screen

d d

9

Refraction

Fisherman use a trident as light is bent at the surface

The fisherman sees the fish and tries to spear it

10

11

Refraction through a glass block

Light bends towards the normal

12

Real and Apparent Depth

A pool appears shallower

13

14

Focal Point

Focal Point

Lenses Two types of lenses

Converging Lens Diverging Lens

15

Dispersion

Breaking up of white light into it’s colours

16

Electromagnetic spectrum

Gamma rays

X-rays Ultra violet

Visible light

Infra red Microwaves

Radio/TV

Each type of radiation shown in the electromagnetic spectrum has a different wavelength and a different frequency:

High frequency, short wavelength

Low frequency,long wavelength

γ

The higher the frequency of the wave, the greater its energy. This makes X-rays dangerous and radio waves

safe

17

Primary and secondary colours

18

UHF and VHF