A blue lamp mainly emits light of wavelength 4500 mathringAThe lamp is rated at 150 W and 8 % of the energy is emitted as visible light. The number of photons emitted by the lamp per second is

Question

A blue lamp mainly emits light of wavelength 4500 mathringAThe lamp is rated at 150 W and 8 % of the energy is emitted as visible light. The number of photons emitted by the lamp per second is (A) 3×1019 (B) 3×1024 (C) 3×1020 (D) 3×1018

Tardigrade Admin · Accepted Answer

Number of photons emitted per second (8 % of P/E)=(8Pλ/100 hc)=(8×150×4500×10-10/100×6.63×10-34×3×108) =3×1019 photons per second

Q. A blue lamp mainly emits light of wavelength $4500 \overset{˚}{A}$ The lamp is rated at $150 W$ and $8%$ of the energy is emitted as visible light. The number of photons emitted by the lamp per second is

$3 \times 1 0^{19}$

$3 \times 1 0^{24}$

$3 \times 1 0^{20}$

$3 \times 1 0^{18}$

Number of photons emitted per second
$\frac{8% o f P}{E} = \frac{8 P λ}{100 h c} = \frac{8 \times 150 \times 4500 \times 1 0 ^{- 10}}{100 \times 6.63 \times 1 0 ^{- 34} \times 3 \times 1 0 ^{8}}$
$= 3 \times 1 0^{19}$ photons per second

Q. A blue lamp mainly emits light of wavelength 4500A˚The lamp is rated at 150W and 8% of the energy is emitted as visible light. The number of photons emitted by the lamp per second is

3×1019

3×1024

3×1020

3×1018