When a force F stretches a rope of mass per unit length rho, the velocity of a wave in the rope is given by You have two ropes of the same length. The mass of the second rope is twice the mass of the first rope. The velocity of a wave in the second rope is the velocity of a wave in the first rope.

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?