Question 139: Dual Nature of Matter and Radiation

Question

A source of monochromatic light liberates 9 $$	imes$$ 1020 photon per second with wavelength 600 nm when operated at 400 W. The number of photons emitted per second with wavelength of 800 nm by the source of monochromatic light operating at same power will be :

Accepted Answer

As we know
$$
\begin{aligned}
&I=\frac{E}{A t}=\frac{n h v}{A t} \Rightarrow \frac{n}{t}=\frac{I A \lambda}{h C} \Rightarrow \frac{n}{t}=\frac{ho \lambda}{h c} \Rightarrow \frac{n}{t}=ho \lambda \\
&\Rightarrow\left(\frac{n}{t}ight)_{2}=\left(\frac{n}{t}ight)_{1} 	imes \frac{p_{2} \lambda_{2}}{p_{1} \lambda 1}=9 	imes 10^{20} 	imes \frac{P}{P} 	imes \frac{800}{600}=12 	imes 10^{20}
\end{aligned}
$$

Answer

12 $$	imes$$ 1020

Answer

6 $$	imes$$ 1020

Answer

9 $$	imes$$ 1020

Answer

24 $$	imes$$ 1020

Dual Nature of Matter and Radiation

A source of monochromatic light liberates 9 $\times$ 1020 photon per second with wavelength 600 nm when operated at 400 W. The number of photons emitted per second with wavelength of 800 nm by the source of monochromatic light operating at same power will be :

Choose the correct answer: