If $2.5 \times 10^{-6\,} N$ average force is exerted by a light wave on a non-reflecting surface of $30\, cm ^{2}$ area during $40$ minutes of time span, the energy flux of light just before it falls on the surface is .................. $W / cm ^{2}$
(Round off to the Nearest Integer)
(Assume complete absorption and normal incidence conditions are there)
If $2.5 \times 10^{-6\,} N$ average force is exerted by a light wave on a non-reflecting surface of $30\, cm ^{2}$ area during $40$ minutes of time span, the energy flux of light just before it falls on the surface is .................. $W / cm ^{2}$
(Round off to the Nearest Integer)
(Assume complete absorption and normal incidence conditions are there)
- [JEE MAIN 2021]
- A
$36$
- B
$16$
- C
$30$
- D
$25$
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