Question

How far apart are the slits to produce a 3rd order bright fringe at an angle of 3.52° if the light source has a wavelength of 2.58x107m?7.33x10 m1.26x105m4.20x106m2.20x107m

Answer 1

Using diffraction grating equation:

$dsin(\theta)=n\lambda$

Where:

$\begin{gathered} d=Distance \\ \theta=Angle=3.52 \\ \lambda=Wavelength=2.58\times10^7 \\ n=integer_{\text{ }}number_{\text{ }}to_{\text{ }}next_{\text{ }}bright_{\text{ }}fringe=3 \end{gathered}$

Solve for d:

$\begin{gathered} d=\frac{\lambda n}{sin(\theta)} \\ d=\frac{(3)(2.58\times10^7)}{sin(3.52)} \\ d\approx1.26\times10^5m \end{gathered}$