Which has a higher energy a photon of violet light with wavelength  or a photon of red light with wavelength $7000{\mathrm{A}}^0(\mathrm{h}=6.625 \times {10}^{–\mathrm{34}} \mathrm{J}.\sec )$

$$\begin{gathered} \mathrm{E}\propto \frac{1}{\mathrm{\lambda }} \\ \mathrm{E}=\frac{\mathrm{hc}}{\mathrm{\lambda }} \end{gathered}$$
Case (i) Energy of a photon of violet light with wavelength $4000{\mathrm{A}}^0$
$$\begin{gathered} \mathrm{E}=\frac{6.626\times {10}^{-34}\mathrm{J}.\mathrm{Sec}\times 3\times {10}^8\mathrm{m}/\sec }{4000\times {10}^{-10}\mathrm{m}} \\ =4.96\times {10}^{-19}\mathrm{J} \end{gathered}$$
Case (ii) Energy of a photon of red light with wave length $7000{\mathrm{A}}^0$
$$\begin{gathered} =\frac{6.626\times {10}^{-34}\mathrm{J}.\sec \times 3\times {10}^8\mathrm{m}/\sec }{7000\times {10}^{-10}\mathrm{m}} \\ =2.83\times {10}^{-19}\mathrm{J} \end{gathered}$$
So violet light has higher energy than red light.