In a laboratory demonstration, a siren producing a continuous note of frequency 500Hz is attached to one end of a solid iron rod of length 2.0m. The other end of the rod projects into air and dips just below the surface of a tank of water. Thus the sound travels successively through iron, air and water.
(a) For each of the three media (iron, air, water) calculate the wavelength of the sound. Take the speeds of sound as: iron 5950m/s, air 340m/s, water 1500m/s.
(b) Compute the factor by which the wavelength changes as the sound moves (i) from iron to air, and (ii) from air to water.
(c) Determine the total number of wavelengths that fit exactly in the 2.0m length of the iron rod.
(d) Explain, using your results, whether nodes formed in the iron rod would coincide with compressions in the air just outside the rod.