27) What is the volume of air passed at the outlet of a rectangular duct whose area of cross section is 1m² and the air velocity by an anemometer is 10m/min?|

28) How the power consumed by the motor varies with its speed in VFD?

29) Which parameter of power supply determines the speed of induction motor?

30) Which type of load consumes more energy in an AC plant system?

31) Which part of electronic filter removes tobacco smoke and odours?