1) In Young's double-slit experiment, green light is incident on the slits. The interference pattern is observed on the screen. Which of the following changes would cause the fringes to be more closely spaced?
a) Reduce the slit separation distance
b) Use red light instead of green light
c) Use blue light instead of green light.
d) Move the screen farther away from the slits
e) Move the light source farther away from the slits.


2) Which of the following statements best explains why the diffraction of sound is more apparent than the diffraction of light under most circumstances?
a) Sound requires a physical medium for propagation.
b) Sound waves are longitudinal, and light waves are transverse.
c) Light waves can be represented by rays while sound waves cannot.
d) The speed of sound in air is six orders of magnitude smaller than that of light.
e) The wavelength of light is considerably smaller than the wavelength of sound.

3) Complete the following sentence: The term coherence relates to
a) the phase relatonship between two waves.
b) the polarization state of two waves.
c) the diffraction of two waves.
d) the amplitude of two waves.
e) the frequency of two waves.

Concepts and Definitions
Linear Superposition, Constructive Interfernce, Destructive Interference, Young's Double-Slit Experiment, Thin Film Interference, Soap Bubbles, Diffraction (Slit Width-vs-Wavelength), Photolithography, Compact Discs, DVD's