Question

A bulb emits light of wavelength 3000
angstroms. The bulb is rated as 200 watt
and 10% of the energy is emitted as light.
How many photons are emitted by the
bulb per second?​

Answer 1

Answer:

Energy emitted per second by the bulb =150×1008J

Energy of 1 photon =λhc=4500×10−106.626×10−34×3×108

                              =4.42×10−19 joule

Let n photons be evolved per second.

∴n×4.42×10−19=150×1008

n=27.2×1018.

Answer 2

Answer:

Energy emitted per second by the bulb =150×1008J

Energy of 1 photon =λhc=4500×10−106.626×10−34×3×108

                              =4.42×10−19 joule

Let n photons be evolved per second.

∴n×4.42×10−19=150×1008

n=27.2×1018.