q20.Why does the light from the Sun appear white? The light is exactly in the mi
ID: 289240 • Letter: Q
Question
q20.Why does the light from the Sun appear white?
The light is exactly in the middle of the visible spectrum, thus appears white.
The light is contains a roughly equal mix of all the colors of the visible spectrum, so it appears white.
The light is only emitted from the Sun’s Hydrogen, which emits only white light.
The light is not emitting any ultra-violet or infra-red light, so it appears white to our eyes.
The light is exactly a wavelength of 500nm, which corresponds to the color white.
q20a When you switch off the lights on your room at night, the walls, the ceiling, and the floor are at a temperature of about 300 K. Why are you not dazzled by the radiation that they emit?
aBecause they do not emit any radiation.
bBecause they are not anything like black bodies.
cHuman eyes cannot see infrared radiation.
dHuman eyes cannot see ultraviolet radiation.
eNothing can radiate below a temperature of 3000 K.
q20b You have two stars of the same luminosity, but different temperature. Which star is likely larger in radius?
aYou do not have enough information to tell
bThe star with the greater temperature
cThe star with the lesser temperature
The light is exactly in the middle of the visible spectrum, thus appears white.
The light is contains a roughly equal mix of all the colors of the visible spectrum, so it appears white.
The light is only emitted from the Sun’s Hydrogen, which emits only white light.
The light is not emitting any ultra-violet or infra-red light, so it appears white to our eyes.
The light is exactly a wavelength of 500nm, which corresponds to the color white.
Explanation / Answer
20) The light contains roughly equal mixture of all the colors of visible spectrum , thus appear white
Light consists of every color in the spectrum, take a pin wheel with ever color of the spectrum on it and spin is fast, it will appear white. The sun is basically every color of the spectrum shining at us on earth.
21) C human eyes cannot see infrared radiations
Any warm body radiates electromagnetic radiation with a spectrum that depends on the temperature. Above 773.15 kelvin there is enough radiation in the visible part of the spectrum to be visible but at lower temperatures most of the radiation is at infrared frequencies or lower. Our eyes are not sensitive to infrared radiation so we do not see it.
22) C
The Luminosity of a star depends on BOTH its temperature and its radius (surface area)
L is proportional to R2 T4.
where R is radius and T is temperature.
so ,according to the above equations. the star with lesser temperature will be larger in radius
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