Question 8: Wave Optics

Question

An interference pattern is observed by
Young’s double slit experiment. If now the
separation between coherent source is halved and the distance of screen from coherent
sources

Accepted Answer

Fringe width $$(W)=\frac{D \lambda}{d}$$
Now, distance between the coherent sources is halved i.e., $$d^{\prime}=d / 2$$ and distance of coherent source and screen is doubled i.e., $$D^{\prime}=2 D$$
$$\begin{aligned}
& 	herefore W^{\prime}=\frac{D^{\prime} \lambda}{d^{\prime}}=\frac{2 D \lambda}{(d / 2)}=\frac{4 D \lambda}{d} \Rightarrow \frac{W^{\prime}}{W}=4 \
& \Rightarrow W^{\prime}=4 W 	ext { (becomes four times) }
\end{aligned}$$

Answer

becomes double

Answer

becomes one-fourth

Answer

remains same

Answer

becomes four times

Wave Optics

An interference pattern is observed by Young’s double slit experiment. If now the separation between coherent source is halved and the distance of screen from coherent sources

Choose the correct answer: