21. The equivalent resistance and leakage reactance of  a transformer can be found out by
(a) Open circuit test
(b) Short circuit test
(c) Polarity test
(d) None of the above

22.Hydro generator is the commercial name of
(a) Round rotor generator
(b) Cylindrical rotors ynchronous generator
(c) Salient poles ynchronous generator
(d) All the above

23. An electrical machine with lower efficiency will have
(a) Less losses
(b) More losses
(c) No losses
(d) Low operating cost

24. The effect of armature reaction under the poles shoes can be limited by
(a) Inter poles
(b) High reluctance pole tips
(c) Compensating windings
(d) All the above

25. DC motors are started by using starters because
(a) To increase the starting current
(b) To reduce the starting current
(c) To increase the speed
(d) None of the above

26. Swinburne’s test cannot be performed on
(a) Shunt motor
(b) Compound motor
(c) Series motor
(d) All the above

27. Which of the following are used as constant speed drive
(a) DC shunt motor
(b) DC series motor
(c) DC compound motor
(d) All the above

28. No load slip of an induction motor is
(a) Large
(b) No slip
(c) Very small
(d) None of the above

29. The relative advantage of a cage motor over a wound rotor motor of same power is
(a) Cage motor is more efficient
(b) Cage motor is less cost
(c) Better operating power factor
(d) All the above

30. The maximum torque of an induction motor is proportional to
(a) Square of supply voltage
(b) Supply voltage
(c) Reciprocal of the square of supply voltage
(d) None of the above

31. Asynchronous motor runs on
(a) AC only
(b) DC only
(c) Both AC and DC
(d) None of the above

32.If the armature coil of DC machine is N turns then number of conductors of any coil side
(a) 2N
(b) N/2
(c) N2
(d) N

33. The distance between two consecutive and similar top coil side is called
(a) back pitch
(b) Front pitch
(c) Winding pitch
(d) Commutator pitch

34. In lap wound machine, the number of brushes used is equal to
(a) Number of poles
(b) 2
(c) Number of turns
(d) Number of commutator segments

35. A moving iron instrument can measure
(a) AC
(b) AC & DC
(c) DC
(d) Pulse

36. The emf developed in any physical system act in such a direction to tend to
(a) Decrease co-energy at constant mmf
(b) Decrease co-energy at constant flux  
(c) Increase the co-energy at constant mmf
(d) Increase the co-energy at constant flux

37. The factor to be considered while selecting the site of a Hydel power plant
(a) Quantity of water available
(b) Head of water
(c) Accessibility of the site
(d) All of the above

38. Specific speed of a turbine is the speed at which it develop 1 meter HP under the head of
(a) 1 metric meter
(b) 1 meter
(c) 1 feet
(d) 1 cubic meter

39. The active recovery voltage depends on
(a) Power factor
(b) Armature reaction
(c) Circuit condition
(d) All the above

40. The highest current that a circuit breaker is capable of breaking at recovery and re striking voltage is 
(a) Breaking capacity
(b) Making capacity
(c) Recovery current
(d) Recovery voltage