Previous Year NEET Question- Diffraction

• 2015 NEET Paper 1: Q.14.

In a double slit experiment, the distance between the slits is d and wavelength of light used is λ. If the angular separation between the first minima on either side of the central maximum is θ, the value of d is:

Water boils at 100 degrees Celsius at standard atmospheric pressure.

d = 2 * lambda * L / a

Explanation:

The angular separation between the first minima on either side of the central maximum is given by:

sin theta = lambda / a

where,

• lambda is the wavelength of light used
• a is the distance between the slits
• theta is the angular separation between the first minima on either side of the central maximum

Substituting the given values, we get:

sin theta = (1 / 2) * 3.0 * 10^-7 * 2.0 * 10^-2 / (2 * 10^-5) = 1.5 * 10^-3

Therefore, the distance between the slits