Physics
The danger signal is red because its wavelength is the …………… and therefore it gets ………… the least.
- least, deviated
- longest, scattered
- longest, dispersed
- least, scattered
Answer
longest, scattered
Reason — When light passes through a medium, shorter wavelengths (such as blue and violet) are scattered more strongly than longer wavelengths (such as red and orange). Hence, red light is often used for danger signals to ensure visibility over longer distances.
Related Questions
Violet light is scattered nearly …………… times more than the red light.
- 4
- 8
- 16
- 9
To an astronaut in a space-ship, the earth appears —
- white
- red
- blue
- black
During the day the sky appears blue, while during sunset it appears reddish. Which reason correctly explain this phenomenon?
- Blue light has higher wavelength, so it gets scattered more during the day.
- Blue light has shorter wavelength, so it gets scattered more during the day.
- Scattering depends only on the intensity and not on the wavelength of the light.
- Red light has shorter wavelength, so it gets scattered more at sunset.
Vehicles use yellow fog lights instead of white while driving in foggy conditions. The correct reason for this is :
- White light is absorbed completely by water droplets.
- Yellow light has a shorter wavelength so it scatters more.
- Yellow light has a longer wavelength, so it scatters less in fog and penetrates farther.
- Yellow light has all seven colours in it.