Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • A beam of electromagnetic radiation of intensity  is comprised of wavelength 

A beam of electromagnetic radiation of intensity 6.4\times10^{-5} W/cm^2 is comprised of wavelength \lambda=310 nm. It falls normally on a metal (work function \phi=2 eV) of surface area 1 cm2. If one in 103 photons ejects an electron, total number of electrons ejected in 1s is 10x (hc=1240 eVnm, 1 eV=1.6 x 10-19J), then x is :-  
Option: 1 11
Option: 2 10
Option: 3 12
Option: 4 13

Answers (1)

best_answer

Energy in 1 second = 6.4 \times 10 ^{-5} \times \1 \ \times 1 = 6.4 \times 10 ^{-5} Joule

Energy (eV) = \frac{6.4 \times 10 ^{-5}}{1.6 \times 10^{-19}} = 4 \times 10^{14} eV

Energy \ of\ one\ photon = \frac{12400}{3100} = 4 \ eV

Number \ of \ photon \ = \frac{4 \times 10^{14}}{4} = 10^{14}

Number \ of \ electrons \ = \frac{10^{14}}{10^3} = 10^{11}

So, \ x = 11

So the correct answer is option 1.

Posted by

Ritika Jonwal

View full answer

JEE Main high-scoring chapters and topics

Study 40% syllabus and score up to 100% marks in JEE

Similar Questions

Trending Articles/News

anam-khan

JEE Main 2024: NTA debars 39 candidates for 3 years on account of using unfair means
anam-khan

JEE Main 2024 session 2 paper 2 answer key objection window closes today; fees
anam-khan

JEE Main 2024 Topper: Farmer’s son Gajare Nilkrishna says ‘keep questioning until you understand’

Latest Question