Measuring with a grating and dispersion
Answers are for parents and teachers.
1
d = 20 μm, n = 1, x = 40 cm, y = 1.2 cm. What is λ in nm?
600
2
The results are 550, 570 and 530 nm. What is the mean wavelength in nm?
550
3
In glass with n = 1.6 what is the speed of light in units of 10⁸ m/s? (c = 3·10⁸ m/s)
1.875 ≈ 1.9
4
Why does sunlight passing through a window pane not split into a spectrum?
In a plane-parallel plate the rays are refracted differently but leave parallel to each other, so the colours recombine.
5
How can astronomers determine the chemical composition of stars without going there?
The lines in a star's light spectrum are characteristic of elements; studying the spectrum reveals the composition.