The number of photons (λ=6630 mathringA) that strike per second on a totally reflecting screen (as shown in figure), so that a force of 1 N is exerted on the screen, is approximately

Question

The number of photons (λ=6630 mathringA) that strike per second on a totally reflecting screen (as shown in figure), so that a force of 1 N is exerted on the screen, is approximately (A) 1023 (B) 1027 (C) 1025 (D) 1026

Tardigrade Admin · Accepted Answer

F=(d p/d t) ⇒ F=((2 p sin θ)/Δ t) ⇒ F=2 n p sin θ[n= number of photon ] ⇒ 1 N=2(n) (h/λ) sin 30° ⇒ n=1027

Q. The number of photons $(λ = 6630 \overset{˚}{A})$ that strike per second on a totally reflecting screen (as shown in figure), so that a force of $1 N$ is exerted on the screen, is approximately

$1 0^{23}$

$1 0^{27}$

$1 0^{25}$

$1 0^{26}$

$F = \frac{d p}{d t} \Rightarrow F = \frac{( 2 p s i n θ )}{Δ t}$
$\Rightarrow F = 2 n p sin θ [n =$ number of photon $]$
$\Rightarrow 1 N = 2 (n) \frac{h}{λ} sin 3 0^{\circ}$
$\Rightarrow n = 1 0^{27}$

Q. The number of photons (λ=6630A˚) that strike per second on a totally reflecting screen (as shown in figure), so that a force of 1N is exerted on the screen, is approximately

1023

1027

1025

1026