Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Engineering
  • A metallic surface with work function of , on heating to a temperature of <img alt="800 \mathr

A metallic surface with work function of 2 \mathrm{eV}, on heating to a temperature of 800 \mathrm{~K} gives an emission current of 1 \mathrm{~mA}. If another metallic surface having the same surface area, same emission constant but work function  4 \mathrm{eV} is heated to a temperature of 1600 \mathrm{~K}, then the emission current will be

Option: 1

1 \mathrm{~mA}


Option: 2

2 \mathrm{~mA}


Option: 3

4 \mathrm{~mA}


Option: 4

None of these


Answers (1)

best_answer

The emission current \mathrm{i=A T^2 S e^{-\phi / k T} }
For the two surfaces\mathrm{ A_1=A_2, S_1=S_2, T_1=800 \mathrm{~K}, T_2=1600 \mathrm{~K}, \phi_1 / T_1=\phi_2 / T_2 }
Therefore, \mathrm{\frac{i_2}{i_1}=\left(\frac{T_2}{T_1}\right)^2=(2)^2=4 \Rightarrow i_2=4 i_1=4 \mathrm{~mA} }

Posted by

vishal kumar

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 2025 registration ends tomorrow; changes introduced in exam this year
anam-khan

BTech Admission 2025 Live: JEE Mains registrations closing tomorrow; VITEEE, MET exam dates out
anam-khan

JEE Main 2025 Live: NTA to close JEE registration on Friday; apply at jeemain.nta.nic.in, correction window

Latest Question