Two narrow slits are illuminated by an ordinary filament bulb
PHYSICS · Single correct · A Level · Physics · Waves · Waves
Problem
Two narrow slits are illuminated by an ordinary filament bulb, yet no steady interference fringes are seen on the screen. Which option best explains this observation?
(a) The light emitted by the bulb is unpolarised.
(b) The path length between the slits and the screen is too short to separate the fringes.
(c) The phase difference between the waves from the two slits changes randomly with time.
(d) The bulb emits a broad range of wavelengths, so the coloured fringes overlap and disappear.