જો કોઇ એક ધાતુ માટે થ્રેશોલ્ડ તરંગલંબાઇ $\lambda _0$, હોય અને આપાત પ્રકાશની તરંગલંબાઇ $\lambda $ હોય, તો ધાતુમાંથી ઉત્સર્જિત ઇલેક્ટ્રોનનો મહત્તમ વેગ કેટલો થશે ?

Question

A${\left[ {\frac{{hc}}{m}\,\left\{ {\frac{{\lambda - {\lambda _0}}}{{\lambda {\lambda _0}}}} \right\}} \right]^{1/2}}$
B${\left[ {\frac{{2hc}}{m}\,\left\{ {\frac{{\lambda _0 - {\lambda }}}{{\lambda {\lambda _0}}}} \right\}} \right]^{1/2}}$
C${\left[ {\frac{h}{m}\,\left( {{\lambda _0} - \lambda } \right)} \right]^{1/2}}$
D${\left[ {\frac{2h}{m}\,\left( {{\lambda } - \lambda _0} \right)} \right]^{1/2}}$

Diffcult

Download our app for free and get started

Solution

b
$h v= h v_0+\frac{1}{2} mv ^2$

$\therefore \frac{1}{2} mv ^2=h v^2 h v_0=\frac{h c}{\lambda}-\frac{h c}{\lambda_0}$

$\therefore v^2=\frac{2 h c}{m}\left[\frac{1}{\lambda}-\frac{1}{\lambda_0}\right]$

$\therefore v ^2=\frac{2 hc }{ m }\left|\frac{\lambda_{-0}-\lambda_0}{\lambda_{00}}\right|^1$

$\left.\therefore v ^2=[ \frac{2 hc }{ m }\left\{\frac{\lambda_{-0}-\lambda^{\prime}}{\lambda_{-0}}\right\}\right]^{\frac{1}{2}}$

Download our app
and get started for free

Similar Questions

Download our appand get started for free

Similar Questions

Download our app
and get started for free