PHYSICS [2 Mark Question Answer]

Colour subtraction means to reflect or absorb a particular colour of light in the presence of other colours of light. For example, a shirt is made of a material that is capable of absorbing green light. So, when white light falls on this shirt, if appears magenta.

We see objects due to the reflection of light falling on them. The colour of an object depends upon the colour of the light reflected by it. The colour of the reflected light depends upon the colour of the light falling on the object.

When any two primary colours are mixed in equal proportions, new colours are produced. The colours produced by mixing any two primary colours are called secondary or composite colours. Yellow, cyan and magenta are the three secondary colours. They are called secondary colours as they are produced by mixing primary colours.

Uses of plane mirrors are :

• Plane mirrors are used as looking glasses.
• They are used in periscopes and kaleidoscopes.
• Army persons use plane mirrors for signalling.
• They are also used in optical instruments and box-type solar cookers to reflect sunrays towards the vessel to be heated.

1. 60°
2. 35°

The word AMBULANCE is printed laterally inverted on an ambulance van so that it reads correctly in the side view mirrors of the vehicles in front of the van. This would allow the vehicles to recognize an ambulance van easily and they could then ensure that the ambulance has enough space to move ahead.