Two monochromatic light sources, A and B, emit the same number of photons per second. The wavelength of A is $\lambda_A = 400 nm$, and that of B is $\lambda_B = 600 nm$. The power radiated by source B is :
Answer & explanation
Correct answer: option 2
More the wavelength, lesser is the kinetic energy and so lesser is the power radiated.
$P = \frac{Nhc}{\lambda}$
$\frac{P_B}{P_A} = \frac{\lambda_A}{\lambda_B} <1$
$\Rightarrow P_B < P_A$