In a Young's double slit experiment, I₀ is the intensity at the central maximum and $\beta$ is the fringe width. The intensity at a point P distant x from the centre will be

• A

  ${\mathrm{I}}_{\mathrm{o}}\cos \frac{\mathrm{\pi x}}{\mathrm{\beta }}$

• B

  $4{\mathrm{I}}_{\mathrm{o}}{\cos }^2\frac{\mathrm{\pi x}}{\mathrm{\beta }}$

• C

  ${\mathrm{I}}_{\mathrm{o}}{\cos }^2\frac{\mathrm{\pi x}}{\mathrm{\beta }}$

• D

  $\frac{{\mathrm{I}}_{\mathrm{o}}}{4}{\cos }^2\frac{\mathrm{\pi x}}{\mathrm{\beta }}$