Question

A 100 watt bulb emits monochromatic light of wavelength 400nm. Calculate the number of photons emitted per second by the bulb.

Answer 1

● Answer -

N = 2×10^20 photons

● Explanation -

Energy of isolated photon is calculated by -

E = hc/λ

E = (6.63×10^-34 × 3×10^8) / (4×10^-7)

E = 4.97×10^-19 J

No of photons emitted per unit time is calculated by -

N = P / E

N = 100 / (4.97×10^-19 J)

N = 2×10^20 photons

Therefore, 2×10^20 photons are emitted.

Answer 2

Answer:

Explanation:

Using E= nhc/λ where n= number of photons