(5) Optics

Question 1

Explain what coherent sources of light mean

Answer 1

Waves in CONSTANT phase difference, same frequency and wavelength.

Question 2

Explain what would happen if red light was replaced by a non laser source emitting white light.
(Double slit)

Answer 2

Central white fringe
All subsidiary maxima composed of a spectrum
Maxima have violet nearest central maximum / Red furthest from centre
Fringe spacing less / maxima are wider

Question 3

Explain the formations of a laser double slit experiment on a screen.

Answer 3

Interference fringes formed
Where light of two slits overlaps (superposes)

Bright fringes are formed where light reinforces ( constructive interference) (crest meets crest).

Dark fringes formed where light (destructively interferes)
(Trough meets crest)

Light from two slits are coherent.