Explain why two flashlights held close together do not produce an interference pattern on a distant screen?

In Young's double -slit experiment butter paper is placed convering one of the slit. How will the interference pattern on a distant screen change if butter paper partially refracts the light through it?

Statement-1: Light from two coherent sources that are not in phase does not produce an interference pattern. Statement-2: Incoherent sources do not produce a sustained interference pattern.

Monochromatic light from a narrow slit illuminates two parallel slits producing an interference pattern on a screen. The separation between the two slits is now doubled and the distance between the screen and the slits is reduced to half. The fringe width

Two independent sources of light will not produce steady interference pattern because

In young's double slit experiment relative intensity at a point on the screen may be defined as ratio of intensity at that point to the maximum intensity on the screen. Light of wavelength 7500overset(@)A A passing through a double slit, produces interference pattern of relative intensity variation as shown in Fig. theta on horizontal axis represents the angular position of a point on the screen (a) Find separation d between the slits. (b) Find the ratio of amplitudes of the two waves producing interference pattern on the screen.

In a Young's double slit experiment, light of 500 nm is used to produce an interference pattern. When the distance between the slits is 0.05 mm, the angular width (in degree) of the fringes formed on the distance screen is close to:

Why don't we hav interference when two candles are placed close to each other and the intensity is seen at a distant scree? What happens if the candles are replaced by laser sources?

In Young's double slit experiment the two slits are d distance apart. Interference pattern is observed on a screen at a distance D from the slits. A dark fringe is observed on the screen directly opposite to one of the slits. The wavelength of light is