If the slit width is much smaller than the wavelength, _________ occurs.

Interference in thin film is because ________.

When a peak and a trough coincide they cancel each other, and a ________ line results.

In medium, the nature of sound waves is ________.

SONAR is a technique that uses _______ usually underwater, as in submarine navigation.

When the sound source moves away from the observer, or the observer from the source, the pitch of the sound heard is ________ the normal pitch.

The shock wave from a supersonic airplane is a __________ shock wave of intense condensations.

The pressure is defined as the magnitude of the _________.

The product of N_A and k is called the _______.

If the two waves combine in such a way that crest meets trough and trough meets crest, they have _________.