JEE Main 1-Sep-2021 Shift 2 Solved Paper

Energy of photon is given as
E=

nhc

λ

...(i)
where, E = energy of photon (50 W),
n = number of photon
h= Planck's constant (6.63×10−34‌Js)
c= speed of light (3×108m∕s)
λ= wavelength of light (795×10−9m)
E = 50 W = 50 J = energy of photon
50J=

n×6.63×10−34Js×3×108m∕s

795×10−9m

⇒ n=

50×795×10−9

6.63×10−34×3×108

=1998.49×1017 =1.998×1020 =2×1020
∴x=2
∴ Answer is 2.