Calculate the number of photons of light of wavelength 3960 mathringA necessary to provide 1 J of energy.

Question

Calculate the number of photons of light of wavelength 3960 mathringA necessary to provide 1 J of energy. (A) 2 × 1020 (B) 2 × 1016 (C) 2 × 1015 (D) 2 × 1018

Tardigrade Admin · Accepted Answer

Applying, E=n (h c/λ) E=1 J , h=6.6 × 10-34 J s , c=3 × 108 m s -1 λ=3960 mathringA=3960 × 10-10 m n=(1 × 3960 × 10-10/6.6 × 10-34 × 3 × 108) =2 × 1018

Q. Calculate the number of photons of light of wavelength $3960 \overset{˚}{A}$ necessary to provide $1 J$ of energy.

$2 \times 1 0^{20}$

$2 \times 1 0^{16}$

$2 \times 1 0^{15}$

$2 \times 1 0^{18}$

Applying, $E = n \frac{h c}{λ}$

$E = 1 J, h = 6.6 \times 1 0^{- 34} J s, c = 3 \times 1 0^{8} m s^{- 1}$

$λ = 3960 \overset{˚}{A} = 3960 \times 1 0^{- 10} m$

$n = \frac{1 \times 3960 \times 1 0 ^{- 10}}{6.6 \times 1 0 ^{- 34} \times 3 \times 1 0 ^{8}}$

$= 2 \times 1 0^{18}$

Q. Calculate the number of photons of light of wavelength 3960A˚ necessary to provide 1J of energy.

2×1020

2×1016

2×1015

2×1018