logo

Ask Questions, Get Answers

 
X
 Search
Want to ask us a question? Click here
Browse Questions
Ad
0 votes

De-Broglie proposed dual nature for electron by putting his famous equation $\lambda = \large\frac{h}{mu}$. Later on Heisenburg proposed uncertainity principle as $\bigtriangleup p .\bigtriangleup x \geq \large\frac{h}{2}(h = \large\frac{h}{2\pi})$ . On the contrary particle nature of electron was established on the basis of photoelectric effect. When a photon strikes the metal surface , it gives up its energy to the electron. Part of this energy (say w) is used by the electron to escape from the metal and the remaining imparts the kinetic energy $\large\frac{1}{2}mu^2$ to the photoelectron. The potential applied on the surface to reduce the velocity of photoelectron to zero is known as stopping potential. The binding energy of electron in a metal is 250 KJ/mol. The threshold frequency of metal is

$(a)\;6\times10^{-12}sec^{-1}\qquad(b)\;6\times10^{14}sec^{-1}\qquad(c)\;6\times10^{10}sec^{-1}\qquad(d)\;6\times10^{12}sec^{-1}$

Can you answer this question?
 
 

1 Answer

0 votes
$hr_{\large\circ} = 250\times10^3J/mol$
$=\large\frac{250\times10^3}{6.023\times10^{23}}J/molecule$
$\therefore r_{\large\circ} = \large\frac{250\times10^3}{6.626\times10^{-34}\times6.023\times10^{23}}$
$=6\times10^{14}sec^{-1}$
Hence answer is (b)
answered Feb 10, 2014 by sharmaaparna1
 

Related questions

Ask Question
student study plans
x
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App
...