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

What is the de-Broglie wavelength of an electron beam accelerated through a potential difference of $25 \mathrm{V}$.

State the laws of photoelectric effect

Name the phenomenon which illustrate the particle nature of light.

If the intensity of incident radiation is doubled, what happens to the kinetic energy of the electron emitted?

Write Einstein photo electric equation. Explain the laws of photoelectric emission on the basis of photoelectric equation.

A $100 \mathrm{W}$ sodium lamp radiates energy uniformly in all directions. The lamp is located at the centre of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of sodium light is $589 \mathrm{nm}$.

 (i) What is the energy per photon associated with the sodium light?

(ii) At what rate are the photons delivered to the sphere?

Light of frequency $7.21\times {10}^{14}\mathrm{Hz}$ is incident on a metal surface. Electrons with a maximum speed of $6.0\times {10}^5\mathrm{Hz}$ are ejected from the surface. What is the threshold frequency for photoemission of electrons?

 Given Planck's constant $h=6.6\times {10}^{-34} \mathrm{Js}$.

 The mass of the electron ${\mathrm{m}}_{\mathrm{e}}=9.1\times {10}^{-31 }\mathrm{kg}$.