A-level Physics (Advancing Physics)/Young's Slits/Worked Solutions
1. A 2-slit experiment is set up in which the slits are 0.03 m apart. A bright fringe is observed at an angle 10° from the normal. What sort of electromagnetic radiation was being used?
So, microwaves were being used.
2. Light, with a wavelength of 500 nm, is shone through 2 slits, which are 0.05 m apart. What are the angles to the normal of the first three dark fringes?
, where n is an odd integer.
Then, substitute in n = 1,3 and 5 to gain corresponding values of θ:
n | θ (°) |
---|---|
1 | 2.9 x 10^{−4} |
3 | 8.6 x 10^{−4} |
5 | 1.4 x 10^{−3} |
3. Some X-rays, with wavelength 1 nm, are shone through a diffraction grating in which the slits are 50 μm apart. A screen is placed 1.5 m from the grating. How far are the first three light fringes from the point at which the normal intercepts the screen?
, where n is an integer.
Then, substitute in n = 1,2 and 3 to gain corresponding values of x:
n | x (m) |
---|---|
1 | 30 x 10^{−6} |
2 | 60 x 10^{−6} |
3 | 90 x 10^{−6} |