A standing wave of the third overtone is induced in a stopped pipe, 7 m long. The speed of sound is The number of antinodes in the standing wave pattern is:

If a clock aboard a space ship traveling at 0.900 c of the speed of light relative to earth chimes once at the beginning of the hour and again when it reads one hour later, how much time would an observer on earth say elapsed between the two chimes?

Light traveling in a medium with a refractive index 1.19 is incident on a plate of another medium with index of refraction 1.79. at what angle of incidence is the reflected light fully polarized?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?