Q143 / 180 · KCET 2007 · Physics
In Young's double slit experiment with sodium vapour lamp of wavelength $589 \mathrm{~nm}$ and the slits $0.589 \mathrm{~mm}$ apart, the half angular width of the central maximum is
- A$\sin ^{-1}(.001)$
- B$\sin ^{-1}(.00001)$
- Correct answerC$\sin ^{-1}(.0001)$
- D$\sin ^{-1}(.) 01$
Solution
In Young's double slit experiment half angular width is given by
$$
\begin{aligned}
\sin \theta &=\frac{\lambda}{d}=\frac{589 \times 10^{-9}}{0.589 \times 10^{-3}}=10^{-3} \\
\Rightarrow \quad \theta &=\sin ^{-1}(0.001)
\end{aligned}
$$
Hence, the correct answer is option: 'C'.