# Math Help - young's double slit equation....

1. ## young's double slit equation....

Calculate the angle of the second-order maximum for monochromatic light of wavelength 550nm if it illuminates

a)a double slit with a slit seperation of 2.0x10^-6m

b)a diffraction grating with 10 500 slits in 1.0m

2. 2nd fringe occurs when m = 2:
$d\sin \theta = m\lambda$

$\left(2.0 \cdot 10^{-6}m\right) \sin \theta = (2)\left(5.5 \cdot 10^{-7} m \right)$

Solve for $\theta$.

For multiple-slit interference with diffraction gratings, we have the same equation as above also with m = 2:
$d\sin \theta = m\lambda$

To find d, note that each slit are presumed to be equally spaced from one another. So, the distance between two slits is:
$d = \frac{1.0 m}{10500} = 9.5238 \cdot 10^{-5} m$