The bottom of a box has a surface area of 58.8 cm 2 . The mass of the box is 12.0 kg. Acceleration due to gravity at sea level is 9.80 m/s 2 . What is the pressure exerted by the box where it rests

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?