Physics [1 Mark Question Answer]

Dispersion of light

In the atmosphere red colour scatters the least.

Infrared region.

Infrared radiations.

The reason is that glass absorbs ultra-violet radiation while the quartz does not absorb them.

The ultra-violet radiations cause skin diseases on the human body.

Infrared radiations.

Ultraviolet region.

X-rays.

Infrared radiations are used in remote control of television and other gadgets.

These are detected by a thermopile.

The wavelength range for the infrared spectrum is from 7900 Å to 107 Å.

The wavelength range for the ultraviolet spectrum is from 100 Å to 4000 Å.

The wavelength range for the visible spectrum is from 4000 Å to 7900 Å.

The red light is deviated at least.

Infrared radiations are used as signals during the war.

Ultraviolet radiation is used for sterilizing purposes.

Microwaves are used for communication.

Infrared radiations are used in photography in fog because they are not much scattered by the atmosphere, so they can penetrate appreciably through it.

Infrared lamps are used in dark rooms for developing photographs since they do not affect the photographic film chemically, but they provide some visibility.

The violet is deviated most.

Infrared radiations are used as signals during the war as they are not visible and they are not absorbed much in the medium.

In the presence of infrared radiations, the temperature recorded by a blackened bulb thermometer rapidly increases.

(i) Infrared lamp, (ii) Fire.

In the presence of ultra-violet radiation, the silver chloride solution becomes dark brown or black.

(i) Sun, (ii) Electric arc.

UV radiations.