Diffraction Grating (Leaving Cert Physics): Flashcards

Optical device splitting light into component wavelengths

Thousands of equally spaced parallel slits

$d$ = distance between centres of adjacent slits

$d = \frac{1}{\text{lines per mm}} \times 10^{-3}$ m

Greater diffraction angles

Single wavelength light

Zero order, $n = 0$

$n\lambda = d \sin \theta$

Order of diffraction (0, ±1, ±2, ±3...)

Wavelength of light (in metres)

Angle of diffraction from straight-through position

$n$ wavelengths

$n_{max} = \frac{d}{\lambda}$

$\sin \theta$ cannot exceed 1

Central spot ($n = 0$)