The ratio of brightness of two stars can be determined by a constant of 2.512 raised to the power of the magnitude difference. the formula
b1
b2
= 2.512(m2 − m1) where b1 and b2 represent the brightness and m1 and m2 refer to the magnitudes of the stars being compared. one star has a magnitude of 0.2, and another star has a magnitude of 2.2. what is the ratio of brightness of these two stars?

8.29 two streams containing pyridine and acetic acid at 25°c are mixed and fed into a heat exchanger. due to the heat-of-mixing effect, it is desired to reduce the temperature after mixing to 25°c using a stream of chilled ethylene glycol as indicated in the diagram. calculate the mass flow rate of ethylene glycol needed. the heat capacity of ethylene glycol at these conditions is approximately 2.8 kj/(kg k), and the enthalpy change of mixing (δmixh) is given below.