In case of _______________ speed control by injecting e.m.f. in the rotor circuit is possible?

Related Mcqs:

1. Besides a constant speed a synchronous rotor possesses which of the following advantages ?

   A. Lower cost
   B. Better efficiency
   C. High power factor
   D. All of the above

2. If 1 A current flows in a circuit, the number of electrons flowing through this circuit is

   A. 0.625 × 10¹⁹
   B. 1.6 × 10¹⁹
   C. 1.6 × 10-¹⁹
   D. 0.625 × 10-¹⁹

3. Rotor of a motor is usually supported on ___________________ bearings?

   A. ball or roller
   B. needle
   C. bush
   D. thrust

4. A wound rotor induction motor is preferred, as compared to squirrel cage induction motor, when major consideration is____________________?

   A. slop speed operation
   B. high starting torque
   C. low windage losses
   D. all of the above

5. The diameter of the rotor shaft for an electric motor depends on which of the following ?

   A. r.p.m. only
   B. Horse power only
   C. Horse power and r.p.m.
   D. Horse power, r.p.m. and power factor

6. An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 4×10-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is____________?

   A. 150msec-1
   B. 384msec-1
   C. 38.4msec-1
   D. 200msec-1

7. The inputs of a NAND gate are connected together. The resulting circuit is _______________?

   A. OR gate
   B. AND gate
   C. NOT gate
   D. None of the above

8. A CE amplifier is also called _______________ circuit?

   A. Grounded emitter
   B. Grounded base
   C. Grounded collector
   D. None of the above

9. Positive logic in a logic circuit is one in which______________?

   A. logic 0 and 1 are represented by 0 and positive voltage respectively
   B. logic 0 and, -1 are represented by negative and positive voltages respectively
   C. logic 0 voltage level is higher than logic 1 voltage level
   D. logic 0 voltage level is lower than logic 1 voltage level

10. In a series–parallel circuit consisting of R1 and R2 in series and connected in parallel with R3, if R1 opens, then R2‘s voltage will:___________?

    A. increase
    B. remain the same
    C. decrease
    D. cannot tell