(a) How does one explain the emission of electrons from a photosensitive surface with the help of Einstein’s photoelectric equation?

(b) The work function of aluminium is 4·2 eV. If two photons each of energy 2·5 eV are incident on its surface, will the emission of electrons take place? Justify your answer.

(c) The stopping potential in an experiment on the photoelectric effect is 1·5 V. What is the maximum kinetic energy of the photoelectrons emitted? Calculate in Joules.

 

 

 
 
 
 
 

Answers (1)
S safeer

(a) When a photon of the energy h\nu is absorbed by an electron in the photosensitive material, a part of the energy absorbed is used up in liberating it from the surface (the work function), 

\therefore The remaining energy appears as the kinetic energy of the photoelectron.

Such that,

K_{max}=h\nu -\phi _{o}\; \; \; \; (\therefore \phi _{o}is \; work\; function)

and if, h\nu > \phi _{o}

 the electron is emitted 

(b) If the two photons each of energy 2.5 eV are incident on the given surface, then the emission of electrons will not take place.

Such that,

energy h\nu, of a single photon, is less than the work function \phi _{o}

\because K_{max}=h\nu -\phi _{o}

if  h\nu < \phi _{o} so, hence, no emission will take place.

(c) Given; the stopping potential (\nu _{o})=1.5V

We know, K_{max}=eV_{o}                (\therefore K_{max}=Maximum kinetic energy )

K_{max}=1.6\times 10^{-19}\times 1.5=2.4\times 10^{-19}Joule

Preparation Products

JEE Main Rank Booster 2021

This course will help student to be better prepared and study in the right direction for JEE Main..

₹ 13999/- ₹ 9999/-
Buy Now
Rank Booster NEET 2021

This course will help student to be better prepared and study in the right direction for NEET..

₹ 13999/- ₹ 9999/-
Buy Now
Knockout JEE Main April 2021 (Subscription)

An exhaustive E-learning program for the complete preparation of JEE Main..

₹ 6999/- ₹ 5/-
Buy Now
Knockout NEET May 2021

An exhaustive E-learning program for the complete preparation of NEET..

₹ 22999/- ₹ 14999/-
Buy Now
Knockout BITSAT 2020

It is an exhaustive preparation module made exclusively for cracking BITSAT..

₹ 4999/- ₹ 1999/-
Buy Now
Exams
Articles
Questions