(Multiple choice)

(1)

Which of the following pairs of light sources are coherent:

(a) Two candles;

(b) One point source and its image in a plane mirror;

(c) Two pinholes uniformly illuminated by the same point source;

(d) Two headlights of a car;

(e) Two images of a point source due to reflection from the front and back surfaces of a soap film.

(2)

A double-slit interference experiment is set up in a chamber that can be evacuated. Using monochromatic light, an interference pattern is observed when the chamber is open to air. As the chamber is evacuated one will note that

(a) The interference fringes remain fixed.

(b) The interference fringes move closer together.

(c) The interference fringes move farther apart.

(d) The interference fringes disappear completely.

(3)

When a diffraction grating is illuminated with white light, the first-order maximum of green light

(a) Is closer to the central maximum than that of red light.

(b) Is Closer to the central maximum than that of blue light.

(c) Overlaps the second order maximum of red light.

(d) Overlaps the second order maximum of blue light.

(4) True or false:

(a) When waves interfere destructively, the energy is converted into heat energy.

(b) Interference is observed only for waves from coherent sources.

(c) In the Fraunhofer diffraction pattern for a single slit, the narrower the slit, the wider the central maximum of the diffraction pattern.

(d) A circular aperture can produce both a Fraunhofer and a Fresnel diffraction pattern.

(e) The ability to resolve two point sources depends on the wavelength of the light.