AQA A Level Physics 3.3. Waves: Summary

diffraction gratings are useful for separating
wavelengths of light, and are used in spectrometers to:
-analyse light from stars
-analyse the composition of a star
-chemical analysis
-measure red shift/ rotation of stars
-measure the wavelength of light from a star
-observe the spectra of materials
-analyse the absorption/ emission spectra in stars




. .
>5. .
blue light has a
shorter wavelength
than red light, so wavelength distance from
the path slit to screen for interferenc
difference will be
D the sources mu
smaller and the
blue maxima will W
fringe
= s spacing
slit
-coherent (con
appear closer to
the centre spacing -monochromat
waves a
- the sam
- a const


the slit width (compared to the s
wavelength) affects how much the spa
path difference = n x waves spread out when diffracted
constructive interference P2
if the slit is made narrower:
-the intensity would decrease
-the fringe spacing would be wider
S2 I

P1



S1 ⑧
path difference = nn
destructive interference
monochromatic
light source a
-




path difference = the
difference in distance -




travelled by two waves
from their sources to the
point where they meet
S ↳





coherence is vital in order to produce an observable interference patt