Question 431: Wave Optics

Question

If two slits in Young's experiment are $$0.4 \mathrm{~mm}$$ apart and fringe width on a screen $$200 \mathrm{~cm}$$ away is $$2 \mathrm{~mm}$$ the wavelength of light illuminating the slits is

Accepted Answer

Fringe width $$W=\frac{D \lambda}{d}$$
Given, $$d=0.4 \mathrm{~mm}=0.04 \mathrm{~cm}, D=200 \mathrm{~cm}$$
$$\begin{aligned}
W & =2 \mathrm{~mm}=0.2 \mathrm{~cm} \
	herefore \quad 0.2 & =\frac{200 	imes \lambda}{0.04} \Rightarrow \lambda=400 \mathrm{~nm}
\end{aligned}$$

Answer

500 nm

Answer

600 nm

Answer

400 nm

Answer

300 nm

Wave Optics

If two slits in Young's experiment are $0.4 \mathrm{~mm} apart and fringe width on a screen 200 \mathrm{~cm} away is 2 \mathrm{~mm}$ the wavelength of light illuminating the slits is

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