61. Regenerative braking is not possible in a series motor.
A. True
B. False
Answer: A
In regenerative braking, the motor acts as a generator. The back emf is more than the terminal voltage in the case of regenerative braking.
62. Regenerative is the best electrical braking among all braking techniques.
A. True
B. False
Answer: A
In regenerative braking, the power is fed back to the source from the battery. The kinetic energy of the motor shaft is converted into electrical energy.
63. Full form of SCIM.
A. Squirrel cage induction motor
B. Solid cage induction motor
C. Square cage induction motor
D. Squirrel cage inverter motor
Answer: A
SCIM stands for squirrel cage induction motor. SCIM rotor is made up of aluminum, and copper bars. There are no armature conductors involved in it.
64. Wound rotor induction motor has better ________ characteristics than Squirrel cage induction motor.
A. Starting
B. Running
C. Modified
D. Quasi-state
Answer: A
A wound rotor induction motor has better starting characteristics because external resistance can be connected to it using slip rings to start the motor. In the case of SCIM, no external resistance can be connected to the rotor side.
65. All circuits are always _________
A. Networks
B. Resistors
C. Capacitors
D. Inductors
Answer: A
The network is defined as the interconnection of electrical elements that may or may not has a closed path. The circuit is defined as the interconnection of an element that must have at least one closed path. All circuits are always networks but vice-versa is not true.
66. The dead network does not have any _________
A. Dependent source
B. Independent source
C. Resistor
D. Capacitor
Answer: B
In the case of the dead network, there are no independent sources available in the electrical circuit. The Thevenin voltage of the circuit is zero because no force is available to drive the current in the circuit.
7. During short circuit condition, the voltage is equal to ________
A. 2 V
B. 0 V
C. 1 V
D. 3 V
Answer: B
During the short circuit condition, the voltage is equal to zero volts. According to Ohm’s law, V=IR=0 V. The value of the current can be positive, negative, or zero.
68. When 5 A current flows into the positive terminal of voltage source 6 V. Calculate the power delivered by the source.
A. -30 W
B. 36 W
C. -43 W
D. 50 W
Answer: A
When the current enters the positive terminal of an element it will always absorb the power and when the current leaves the positive terminal it will deliver the power. Power delivered is
-5×6=-30 W.
69. When 10 A current leaves the positive terminal of resistance 5Ω. Calculate the power absorbed by the resistance.
A. -308 W
B. 500 W
C. -63 W
D. 60 W
Answer: B
When the current enters the positive terminal of an element it will always absorb the power and when the current leaves the positive terminal it will deliver the power. The power delivered is
100×5=500 W.
70. Calculate the equivalent inductance when two inductors are connected in a series of values 4 H and 9 H.
A. 13 H
B. 10 H
C. 11 H
D. 12 H
Answer: A
When two inductors are connected in series their equivalent inductance is equal to the sum of the individual inductances.
