Definition :A real image is an image that forms on a screen.A virtual image is an image that cannot be formed on a screen

Types of mirror Usage Plane mirror - Makes living room look spacious - Helps a dancer to correct his movementConcave mirror - Helps to magnify the image to make it easier for somene to apply make up - Used by a dentist to see the patient's teethConvex mirror - Used a safety feature at dangerous comer of a road - Help a shopkeeper to see every comer of the supermarket to prevent thef

- Light travels in straight lines - Light travels faster than sound- Light can be dispersed by water droplets in the sky

Light reflected obeys the Law of Reflection: The incident ray, the reflected ray and the normal line all lie on the same plane The angle of incidence, i is equal to the angle of reflection, r

Definition : The illusions occur as the change in the direction of movement of light when light travels through two mediums of different densities

Primary colour - Basic colour that cannot be produced through colour mixing (red, blue and green). Secondary colour - Colours produced from mixing of two colours ( cyan, yellow and magenta).

Definition : Subtraction of light is the light which has the same colour as the colour of the opaque obejcts that will reflect directly into our eyes

Examples of Addition and Subtraction of Light: - Coloured television - Coloured lights on stage - Coloured lights in a stadium - Coloured lights at KLCC

Definition Scattering of light occurs when light is reflected in all directions by clouds on particles in the air.

During midday : Blue light is scattered the most in all directions by the tiny particles in the atmosphere. Therefore, the sky looks blue during midday. During sunset : The sun is at the horizon Red and orange light are less scattered and will go through the atmosphere to reach our eyes. Other coloured lights such as blue light are scattered away.Therefore, the sky looks reddish during sunset.