A resistor and an inductor of negligible resistance are connected in series to an a. c. supply. The p. d. across the resistor is 20V and the p. d. across the inductor is 50V. Calculate the supply voltage and the phase angle betweenvoltage and current.

Determine whether or not it is possible to compress air adiabatically from k to 140 kpa and 400 k. what is the entropy change during this process?

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.