Advertisements
Advertisements
प्रश्न
Why is the colour red used as a sign of danger?
उत्तर
In the visible light, the wavelength of red light is longest, the light of red colour is scattered least by the air molecules of the atmosphere and therefore the light of red colour can penetrate to a longer distance. Thus, red light can be seen from the farthest distance as compared to the other colours having the same intensity. Hence, it is used for danger signal so that the signal may be visible from the far distance even in fog, etc.
APPEARS IN
संबंधित प्रश्न
Name three factors on which the deviation produced by a prism depends and state how does it depend on the factors stated by you.
Which colour of white light travels fastest in glass?
In following figure shows a thin beam of white light from a source S striking on one face of a prism.
Complete the diagram to show effect of prism on the beam and to show what is seen on the screen.
In following diagram shows a thin beam of white light from a source S striking on one face of a prism.
What conclusion do you draw from the observation in part (b) above?
Fig shows part of the arrangement for obtaining pure spectrum.
(a) Complete thediagram and show how to obtain a pure spectrum.
(b) What are the conditions necessary for obtaining a pure spectrum?
Explain, why quartz prism is required for obtaining the spectrum of ultra-violet light?
Draw a neat diagram to show the arrangement you would use to project a pure spectrum of white light on a screen.
Which colour of white light travels slowest, in glass?
The wavelengths for the light of red and blue colours are nearly 7·8 × 10-7 m and 4·8 × 10-7 m respectively.
Which colour has greater speed in glass?
