Light is a form of energy that travels away from the source that produces it at a speed of 3×10⁸ m s^-1

Crooke’s Radiometer

• Converts light energy into kinetic energy.
  - shows that light is a form of energy

Light usually travels in straight lines

Reflection of Light

• The bouncing of light from the surface of an object.

• There are two types of reflection, diffuse and regular.

Diffuse Reflection

• When light strikes a matt surface (non smooth surface) the reflected light is scattered in all directions.

• Most everyday objects are visible by light which has been diffusely reflected from them.

Regular Reflection

• If the surface that the light strikes is silvered and polished smooth (e.g. a mirror) the light is not scattered and reflected directly.

Laws of Reflection of Light

Law 1:

• The incident ray, the normal at the point of incidence, and the reflected ray all lie in the same plane.

Law 2:

• The angle of incidence is equal to the angle of reflection.

Optics

There are two types of images:
- real images
- virtual images

Virtual Image:
An image formed by the apparent intersection of rays.
A virtual image cannot be formed on a screen.

Image in Plane Mirror:
A virtual/upright/the same distance behind the mirror as the object is infront of the mirror.
Objects are flipped (lateral inversion) e.g. ambulance in rear view mirror

The apparent movement of one object relative to another due to the motion of the observer is called parallax. The object that is farthest away appears to move with the observer.