A radio transmitter radiated 1 kW power at a wavelength 198.6 m. How many photons does it emit per second?
Answer & explanation
Correct answer: option 3
Here, number of photons emitted per second,
$n=\frac{P}{E}=\frac{P}{hv}=\frac{Pλ}{hc}$ $(∵ v=\frac{c}{λ})$
$=\frac{1000×198.6}{6.6×10^{-34}×3×10^8}=10^{30}$