Question

A 25w bulb emits monochromatic light of wavelength of 0.57um calculate the rate of emission of quant per second

Answer 1

Answer: refer to the image

Answer 2

Explanation:

The energy of one photon is

E=

λ

hc

=

0.57×10

−6

6.626×10

−34

Js×3×10

8

m/s

=3.487×10

−19

J .

25 watt corresponds to 25 J per second.

The number of photons emitted per second is

3.487×10

−19

25

=7.17×10

19

/s.