d
\(\phi \,\, = \,\,2.3\,\,eV\) અને \(\,\lambda \,\, = \,\,4.8\,\, \times \,\,1{0^{ - 7}}\,m\,\, = \,\,4800\,\,\mathop A\limits^ \circ  \)

\(K.E{._{\max .}} = \,\,\,\frac{{hc}}{\lambda }\,\, - \phi \,\,\,\)

\( = \,\,\,\frac{{(6.62\,\, \times \,\,{{10}^{ - 34}}\,Js)\,\,(3\,\, \times \,\,{{10}^8}m{s^{ - 1}})}}{\lambda }\,\, - \,\phi \,\,\)

\( = \,\,\frac{{12400\,\,e\,\,V\,\mathop A\limits^ \circ  }}{\lambda }\,\, - \,\,\phi \)

\(K.E{._{\max .}} = \,\,\,\left[ {\frac{{12400}}{{4800}}\,\, - \,\,2.3} \right]\,\,\,eV\)

\( \Rightarrow \,\,K.E{._{\max }} = \,\,(2.6\,\, - \,\,2.3)\,\,eV\,\, = \,\,0.3\,\,eV\)