Question

Two slits are illuminated by a 602 nm light. The angle between the zeroth-order bright band at the center of the screen and the fourth-order bright band is 17.4 ◦ . If the screen is 138 cm from the double-slit, how far apart is this bright?

Answer 1

Answer:

y = 43.2 cm

Explanation:

As we know by the formula of diffraction we have

$a sin\theta = N\lambda$

here we have

$\theta = 17.4$

N = 4

$\lambda = 602 nm$

now we have

$a sin(17.4) = 4(602\times 10^{-9})$

$a = 8.05 \times 10^{-6} m$

now the distance of screen is 138 cm

now we can say

$\frac{y}{L} = tan\theta$

$y = L tan(\theta)$

$y = 138 tan(17.4) = 43.2 cm$