Question: The synchronous motor is not inherently self-starting because_______________?

• 1. the force required to accelerate the rotor to the synchronous speed in an instant is absent
• 2. the starting device to accelerate the rotor to near synchronous speed is absent
• 3. a rotating magnetic field does not have enough poles
• 4. the rotating magnetic field is produced by only 50 Hz frequency currents

Question: When V is the applied voltage, then the breakdown torque of a synchronous motor varies as_________?

• 1. V
• 2. V312
• 3. V2
• 4. 1/V

Question: A three-phase synchronous motor will have_____________?

• 1. no slip-rings
• 2. one slip-ring
• 3. two slip-rings
• 4. three slip-rings

Question: In case one phase of a three-phase synchronous motor is short-circuited the motor will____________?

• 1. not start
• 2. run at 2/3 of synchronous speed
• 3. run with excessive vibrations
• 4. take less than the rated load

Question: Synchronous motors are generally not self-starting because:

• 1. the direction of rotation is not fixed
• 2. the direction of instantaneous torque reverses after half cycle
• 3. startes cannot be used on these machines
• 4. starting winding is not provided on the machines

Question: “Maximum power output is obtained from a network when the load resistance is equal to the output resistance of the network as seen from the terminals of the load”. The above statement is associated with____________?

• 1. Millman’s theorem
• 2. Thevenin’s theorem
• 3. Superposition theorem
• 4. Maximum power transfer theorem

Question: A capacitor is generally a____________?

• 1. bilateral and active component
• 2. active, passive, linear and nonlinear component
• 3. linear and bilateral component
• 4. non-linear and active component

Question: Kirchhoff s law is applicable to____________?

• 1. passive networks only
• 2. a.c. circuits only
• 3. d.c. circuits only
• 4. both a.c. as well d.c. circuits

Question: Kirchhoff s voltage law applies to circuits with____________?

• 1. nonlinear elements only
• 2. linear elements only
• 3. linear, non-linear, active and passive elements
• 4. linear, non-linear, active, passive, time varying as wells as time-in-variant elements

Question: If resistance across LM in Fig. 2.30 is 15 ohms, the value of R is____________?

• 1. 10 Q
• 2. 20 Q
• 3. 30 Q
• 4. 40 Q