Q9 / 90 · KVPY 2010 (SB/SX) · Chemistry
The energy of a photon of wavelength $\mathrm{k}=1$ meter is (Planck's constant $=6.625 \times 10^{-34} \mathrm{Js}$, speed of light = $\left.3 \times 10^{8} \mathrm{~m} / \mathrm{s}\right)$
- Correct answerA$1.988 \times 10^{-23} \mathrm{~J}$
- B$1.988 \times 10^{-28} \mathrm{~J}$
- C$1.988 \times 10^{-30} \mathrm{~J}$
- D$1.988 \times 10^{-25} \mathrm{~J}$
Solution
$$
\begin{array}{l}
E=\frac{h c}{\lambda}=\frac{6.02 \times 10^{-34} \times 3 \times 10^{8}}{1} \\
E=1.988 \times 10^{-23} \mathrm{~J}
\end{array}
$$
Hence, the correct answer is option: 'A'.