Question

In a Young's double slit experiment, green light is incident on the two slits. The interference pattern is observed on a screen. Which of the following changes would cause the observed fringes to be more closely spaced –

• A. Reducing the separation between the slits
• B. Using blue light instead of green light.
• C. Used red light instead of green light
• D. Moving the light source further away from the slits

Answer 1

Answer: (B)

Using blue light instead of green light.

Answer 2

b = $\frac{\lambda D}{d}$

if d is decreased b will increase.

l_B < V_G \ using blue light b will decrease