181. |
Power produced by a star is 4×1028 W. If the average wavelength of the emitted radiation is considered to be 4500 Å, the number of photons emitted in 1 s is _____ .
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Answer:
Option (b) |
182. |
What should be the ratio of de-Broglie wavelengths of an atom of nitrogen gas at 300 K and 1000 K. Mass of nitrogen atom is 4.7×10-26 kg and it is at 1 atm pressure. Consider it as an ideal gas.
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Answer:
Option (d) |
183. |
Monochromatic light of wavelength 3000 Å is incident normally on a surface of area . If the intensity of light is , the number of photons being on this surface in one second is _____ .
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Answer:
Option (a) |
184. |
A star which can be seen with naked eye from Earth has intensity 1.6×10-9 W m-2 on Earth. If the corresponding wavelength is 560 nm, and the diameter of the lens of human eye is 2.5×10-3 m , the number of photons entering in our eye in 1 s is _____ .
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Answer:
Option (b) |
185. |
Find the velocity at which mass of a proton become 1.1 times its rest mass, mp=1.6×10-27 kg Also, calculate corresponding temperature. For simplicity, consider a proton as non-interacting ideal-gas particle at 1 atm pressure.
(c=3×108 ms-1 , kB=1.38×10-23 SI )
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Answer:
Option (a) |
186. |
Output power of He-Ne LASER of low energy is 1.00 mW. Wavelength of the light is 632.8 nm. What will be the number of photons emitted per second from this LASER?
(h=6.625×10-34 J.sec)
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Answer:
Option (d) |