Embibe Experts Solutions for Chapter: Dual Nature of Radiation and Matter, Exercise 1: Manipur Board-2018

Calculate the wavelength of a signal of frequency $10 \mathrm{KHz}$.

Light of $5000\stackrel{\mathrm{o}}{\mathrm{A}}$ falls on a photo-sensitive plate with photoelectric work function of $1.9 \mathrm{eV}$. Calculate the kinetic energy of the emitted photoelectrons. $\left[\mathrm{h}=6.6\times {10}^{-34} \mathrm{Js}; 1\mathrm{eV}=1.6\times {10}^{-19} \mathrm{J}\right]$

Light of frequency $1.5$ times the threshold frequency is incident on a photosensitive material.If the frequency is halved and intensity is doubled, the photoelectric current becomes

Find the d-Broglie wavelength of an electron accelerated through a potential difference of $60 \mathrm{V}$.

In the figure shown, two monochromatic radiations of intensities ${\mathrm{I}}_1$ and ${\mathrm{I}}_2$ a $\left({\mathrm{I}}_1>{\mathrm{I}}_2\right)$ having the same frequency are in turns incident on a photo sensitive surface causing photo electric emission. Curve $\mathrm{A}$ and $\mathrm{B}$ show the variation of photo electric current with accelerating potential. Identify the curves representing radiation with intensity ${\mathrm{I}}_1$ and ${\mathrm{I}}_2$ giving reason. Also give reason why the two curves have the same stopping potential ${\mathrm{V}}_0$.

What is the de-Broglie wavelength of an electron with kinetic energy of $120 \mathrm{eV}$?

Define threshold frequency in photoelectric effect and describe the failaure of wave theory to explain the existence of a threshold frequency for a photosensitive material.

A laser produces monochromatic light of wavelength $530.4 \mathrm{nm}$. The power emitted is $3.0 \mathrm{mW}$. The number of photons emitted per second on an average is $\left(\mathrm{h}=6.63\times {10}^{-34} \mathrm{Js}, \mathrm{c}=3\times {10}^8{\mathrm{ms}}^{-1}\right)$