Question

A double slit is illuminated by light of wavelength 6000Å. The silt are 0.1 cm apart and the screen is placed 1m away. The angular position of 10^th maximum in radian is :

• A. 2×10^-4
• B. 6×10^-4
• C. 3×10^-4
• D. 1×10^-4

Answer 1

Answer: (B)

6×10^-4

Answer 2

Using,$x = \frac{n\lambda D}{d}$

If $\theta$is angle of diffraction,

Then, $\sin\theta = \frac{x}{D} = \frac{n\lambda}{d}$

Here, $n = 10,\lambda = 6000Å = 6 \times 10^{- 7}m,$

$d = 0.1cm = 10^{3}m$

$\therefore\sin\theta = \frac{10 \times 6 \times 10^{- 7}}{10^{- 3}} = 6 \times 10^{- 3}$

Since $\theta$ is small

$\therefore\theta = \sin\theta = 6 \times 10^{- 3}$ radian