As 390-g of hot milk cools in a mug, it transfers 30,000 j of heat to the environment.
how does the temperature of the milk change? (cmilk = 3.9 j/g°c)
a) it increases by 77°c.
b) it decreases by 77°c.
c) it increases by 20°c.
d) it decreases by 20°c.

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?