Question

A 2 mW laser operates at a wavelength of 500 nm. The number of photons that will be emitted per second is [Given Planck’s constant h = 6.6 × 10⁻³⁴ Js, speed of light c = 3.0 × 10⁸ m/s]
(A) 1 × 10¹⁶ (B) 1.5 × 10¹⁶
(C) 2 × 10¹⁶ (D) 5 × 10¹⁵

Answer 1

Answer:

B) 1.5*10^16

Explanation:

P=  

λ

n.hc

​  

 

n=  

h.c

Pλ

​  

 

=  

6.6×10  

−34

×3×10  

8

 

2×10  

−3

×500×10  

−9

 

​  

 

=1.5×10  

16