Question 6: Wave Optics

Question

Red light of wavelength 5400 $\mathop A\limits^o $ from a
distant source falls on a slit 0.80 mm wide.
Calculate the distance between first two dark
bands on each side of central bright band in
the diffraction pattern observed on a screen
place 1.4 m from the slit.

Accepted Answer

Here, wavelength ($\lambda$) = 5400 $\mathop A\limits^o=5.4	imes10^{-7}$ m, $a=0.80 \mathrm{~mm}=8 	imes 10^{-4} \mathrm{~m}, D=1.4 \mathrm{~m}$
$	herefore$ Distance between first two dark bands on each side of central maximum is the width of central maximum
$\begin{aligned}
& =2 x=\frac{2 \lambda D}{d} \
& =\frac{2 	imes 5.4 	imes 10^{-7} 	imes 1.4}{8 	imes 10^{-4}} \
& =1.89 	imes 10^{-3} \mathrm{~m}=1.89 \mathrm{~mm}
\end{aligned}$

Answer

1.89 mm

Answer

4 mm

Answer

1 mm

Answer

3 mm

Wave Optics

Red light of wavelength 5400 \mathop A\limits^o from a distant source falls on a slit 0.80 mm wide. Calculate the distance between first two dark bands on each side of central bright band in the diffraction pattern observed on a screen place 1.4 m from the slit.

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