If the transformer has fully loaded with 0.9 lagging power factor load and the transformer core power losses is 120 W, then the calculated
transformer efficiency is

The crank case of an automobile is 80 cm long 30 cm wide and 10 cm deep. find out the rate of heat flow from the crank case to the atmosphere when the automobile is moving at 90 km/hr. assume that the vibration of the engine and the chassis iaduce the transition from laminar to turbulent boundary layer may be considered over the entire surface. also find out the drag force on the total surface of the crank case. take the same average convective heat transfer coefficient and average shear stress for front and rare surfaces as for the bottom rnd sides crank case surface temperature is 75°c and atmospheric air temperature is 5 c