Element x has a mass number of 40 and an atomic number of 20, and element y has a mass number of 56 and an atomic number of 26. element x has
more neutrons and fewer electrons than element y.
more neutrons and electrons than element y.
fewer neutrons and electrons than element y.
fewer neutrons and more electrons than element y.

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?