Question

In a Young's double slit experiment, 12 fringes are observed to be formed in a certain region of the screen when light of wavelength 600 nm is used. If the light of wavelength 400 nm is used, the number of fringes observed in the same region of the screen will be.

• A. 12
• B. 18
• C. 24
• D. 8

Answer 1

Answer: (B)

18

Answer 2

$n_1 \lambda_1 = n_2 \lambda_2$