Optics Question 507
Question: A screen receives 3 watt of radiant flux of wavelength 6000 Å. One lumen is equivalent to $ 1.5\times {{10}^{-3}}watt $ of monochromatic light of wavelength 5550 Å. If relative luminosity for 6000 Å is 0.685 while that for 5550 Å is 1.00, then the luminous flux of the source is
Options:
A) $ 4\times 10^{3}lm $
B) $ 3\times 10^{3}lm $
C) $ 2\times 10^{3}lm $
D) $ 1.37\times 10^{3}lm $
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Answer:
Correct Answer: D
Solution:
$ \varphi =\frac{3}{1.5\times {{10}^{-3}}}\times 0.685 $
$ =1.37\times 10^{3}lumen $
