The number of photons emitted per second by a 60 W source of monochromatic light of wavelength 663 nm is (h=6.63× 10-34Js)

Question

The number of photons emitted per second by a 60 W source of monochromatic light of wavelength 663 nm is (h=6.63× 10-34Js)  (A)  4× 10-20  (B)  1.5× 1020  (C)  3× 10-20  (D)  2× 1020

Tardigrade Admin · Accepted Answer

Energy, E=(nhc/λ ) ⇒ 60× 1 Js=(n× 6.63× 10-34Js× 3× 108m/663× 10-9m) [ ∵ power=(energy/time) ] ∴ n=(60× 1× 663× 10-9/6.63× 10-34× 3× 108) =2× 1020

Q. The number of photons emitted per second by a $60 W$ source of monochromatic light of wavelength $663 nm$ is $(h = 6.63 \times 10^{- 34} J s)$

$4 \times 10^{- 20}$

$1.5 \times 10^{20}$

$3 \times 10^{- 20}$

$2 \times 10^{20}$

$1 \times 10^{- 20}$

Q. The number of photons emitted per second by a 60W source of monochromatic light of wavelength 663nm is (h=6.63×10−34Js)

4×10−20

1.5×1020

3×10−20

2×1020

1×10−20