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The relative luminosity of wavelength 60...

The relative luminosity of wavelength 600 nm is 0.6. Find the radiant flux of 600 nm needed to produce the same brightness sensation as produced by 120 W of radiant flux at 555 nm.

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The correct Answer is:
B
Relaive luminousity
Luminous flux of a source of
`=(given wavelength)/(Luminous flux of a source of)
55 nm of same poerre
`:.` Let the radiant flux needed by P watt
So, `0.6=(Luminous flux of source P watt)/(684P)`
`rarr Luminous flux of teh source (685P)x0.6=120x685`
`rarr P=120/0.6=200W
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