Q10 / 120 · VITEEE 2019 · Chemistry

The wavelengths of two photons are $2000 Å$ and $4000 Å$ respectively. What is the ratio of their energies?

  • A
    $1 / 4$
  • B
    4
  • C
    $1 / 2$
  • Correct answer
    D
    2

Solution

$$ \begin{array}{l} \quad \mathrm{E}_{1}=\mathrm{h} \cdot \frac{\mathrm{c}}{\lambda_{1}} ; \quad \mathrm{E}_{2}=\mathrm{h} \cdot \frac{\mathrm{c}}{\lambda_{2}} \\ \frac{\mathrm{E}_{1}}{\mathrm{E}_{2}}=\frac{\mathrm{hc}}{\lambda_{1}} \times \frac{\lambda_{2}}{\mathrm{hc}}=\frac{\lambda_{2}}{\lambda_{1}}=\frac{4000}{2000}=2 \end{array} $$

Hence, the correct answer is option: 'D'.

Relevant Questions