b
\(K\) કણ \( = \,\,\frac{1}{2}\,m{\upsilon ^2},\,\) \(\lambda \,\, = \,\,\frac{h}{{m\upsilon }}\)

\( \Rightarrow \,\,K\) કણ \( = \,\,\frac{1}{2}\,\left( {\frac{h}{{\lambda \upsilon }}} \right)\,\,.\,\,{\upsilon ^2}\, = \,\,\frac{{\upsilon h}}{{2\lambda }}\)

\( \Rightarrow \,\,K\) કણ \( = \,\,\frac{{hc}}{\lambda }\)

\(\therefore \,\,K\) કણ / \(K\) ફોટોન \( = \,\,\frac{\upsilon }{{2c}}\,\, = \,\,\frac{{2.25\,\, \times \,\,{{10}^8}}}{{2\,\, \times \,\,3\,\, \times \,\,{{10}^8}}}\,\, = \,\,\frac{3}{8}\,.\)