Question

In a double slit experiment, the separation between the slits is d = 0.25 cm and the distance of the screen D = 100 cm from the slits, If the wavelength of light used is $\lambda =6000\stackrel{\text{o}}{\text{A}}\text{and}{\text{I}}_{\text{0}}$ is the intensity of the central bright fringe, the intensity at a distance $y=4\times {10}^{-5}$ m from the central maximum is

• A. $I_0$
• B. $I_0$/2
• C. 3$I_0$/4
• D. $I_0$/3

Answer 1

The correct option is A $I_0$

It is given that,

$d=0.25cm$

$D=100cm$

$\lambda =6000\dot{A}=6\times {10}^{-7}m$

For central maximum

$x=\frac{Dn\lambda }{d}$

$x=\frac{100\times 6\times {10}^{-7}}{0.25}$

$x=4\times {10}^{-5}$

Intensity at this point is $I_0$

At $y=4\times {10}^{-5}m$

Intensity will be $I_0$