Give reason for the following :
(i) Infrared radiations are used for photography in fog.
(ii) Infrared radiations are used for signals during the war.
(iii) The photographic darkrooms are provided with the infrared lamps.
(iv) A rock salt prism is used instead of a glass prism to obtain the infrared spectrum.
(v) A quartz prism is required for obtaining the spectrum of the ultraviolet light.
(vi) Ultraviolet bulbs have a quartz envelope instead of glass.
Give reason for the following :
(i) Infrared radiations are used for photography in fog.
(ii) Infrared radiations are used for signals during the war.
(iii) The photographic darkrooms are provided with the infrared lamps.
(iv) A rock salt prism is used instead of a glass prism to obtain the infrared spectrum.
(v) A quartz prism is required for obtaining the spectrum of the ultraviolet light.
(vi) Ultraviolet bulbs have a quartz envelope instead of glass.
(i) Infrared radiations are used in photography in fog because they do not scatter much and can penetrate appreciably through it.
(ii) Infrared radiations are used as signals during the war as they are not visible and they are not absorbed much in the medium.
(iii) The infrared lamps provide some visibility without affecting the photographic film, hence they are used in photographic darkrooms.
(iv) This is because rock-salt prism does not absorb infrared radiations whereas a glass prism absorbs them.
(v) This is because quartz doesn't absorb UV radiations.
(vi) Ultraviolet radiations can pass through quartz but are absorbed by glass. This is why ultraviolet bulbs have an envelope made of quartz instead of glass.
(i) Infrared radiations are used in photography in fog because they do not scatter much and can penetrate appreciably through it.
(ii) Infrared radiations are used as signals during the war as they are not visible and they are not absorbed much in the medium.
(iii) The infrared lamps provide some visibility without affecting the photographic film, hence they are used in photographic darkrooms.
(iv) This is because rock-salt prism does not absorb infrared radiations whereas a glass prism absorbs them.
(v) This is because quartz doesn't absorb UV radiations.
(vi) Ultraviolet radiations can pass through quartz but are absorbed by glass. This is why ultraviolet bulbs have an envelope made of quartz instead of glass.
