UPSEE Solved Model Paper 5

2.9 × 1015
nh

c

λ

= E
where n = number of photons
h = planck's constant = 6.6 × 10−34 Js
c = speed of light = 3 × 108 m/s
λ = 5890

0

A

= 5890 × 10−10 m
E = 1 mw = 10−3

J

S

Substitute get n
n =

Eλ

hc

=

10−3×5890×10−10

6.6×10−34×3×108

= 2.97 × 1015