Bright and dark fringes are seen on a screen when light from a single source reaches two narrow slits a short distance apart.The number of fringes per unit length on the screen can be halved

Question

Quizplus · Accepted Answer

The number of fringes per unit length on the screen is given by the equation: N = (Δyλ)/d, where Δy is the distance between consecutive bright or dark fringes, λ is the wavelength of the light, and d is the distance between the two slits. To halve the number of fringes per unit length, we need to either double Δy, halve λ, or double d. Option A only changes d, so it is not enough to halve N. Option B only changes λ, so it is not enough either. Option E only changes the width of the slits, which is not directly related to N. Option C changes both d and λ, but it is not clear whether the changes would result in halving N. Therefore, the best choice is D, which includes any of the above changes.

Bright and Dark Fringes Are Seen on a Screen When