Ques 21. What is the power consumed by the resistor of 20 ohms connected across a 100-volt source?
300 W
100 W
500 W✔
50 W
Power is given as
P = V2/R
P = 100 x 100/20
= 500 W
Ques 22. For the circuit shown in the figure Norton’s equivalent current source at terminals, A and B is given by
20 ∠0 A
10 ∠0 A
14 ∠36.86 A
16 ∠36.86 A
Ques 23. Which of the following motor is prepared for tape recorders?
Hysteresis Motor✔
Two Value capacitor motor
Universal Motor
Shaded Pole Motor
Hysteresis motor develops hysteresis torque which is extremely steady both in amplitude and phase
Ques 24. A silent pole synchronous motor is operating at one-fourth full load if the field current is suddenly switched off, it would?
Run at super-synchronous Speed
Stop Running
Run at sub-synchronous Speed
Continue to run at synchronous speed✔
Silent pole synchronous motor runs either at synchronous speed or not at all. That is while running, it maintains a constant speed. The speed is independent of load.
Ques 25. Thevenin’s theorem cannot be applied to
Passive circuit
Active Circuit
Nonlinear Circuit✔
Linear circuit
Most of the time we want to analyze any circuit using a mathematical equation that can be applied only to linear circuits so before going to the analysis we have to define our linear range Thevenin’s theorem is also a mathematical method for the solution of a circuit
So despite all things, we can analyze the linear behavior by Thevenin theorem and can’t analyze nonlinear behavior using mathematical equations.
The superposition theorem is being used to prove Thevenin’s and because the superposition can be applied only to linear circuits we get the same result for Thevenin’s theorem.
Ques 26. The motor used in a small lathe is usually
D.C shunt motor✔
3 phase synchronous motor
Single-phase capacitor run motor
Universal Motor
DC shunt motor is a constant speed motor Lathe machine requires to be run in a constant speed hence DC shunt motor is used in lathe machines
Ques 27. Creeping in a single-phase induction type energy meter may be due to
Over Voltage
Vibrations
Overcompensation for Friction
All of the above✔
The slow but continuous rotation of the energy meter when only the pressure coil is excited and there is no current flowing through the current coil (i.e under no-load conditions) is known as creeping.
Creeping occurs due to
Overcompensation for friction.
The supply voltage is more than the normal voltage
Stray magnetic field
Vibration
Ways to prevent creeping :
In order to prevent creeping two holes of the same radius is drilled on the opposite side of the spindle, the disc will stop when one of the holes comes under the shunt magnet.
Ques 28. Baseload of a power station stands for?
2-4 hours/day
12-24 hours/day✔
8-12 hours/day
4-8 hours/day
The base load on a grid is the minimum level of demand on an electrical grid over a span of time, usually 12-24 hours a day. Baseload power sources are power stations that can economically generate the electrical power needed to satisfy this minimum demand.
Ques 29. The aluminum conductor of size ______ is used for a subcircuit in the domestic wiring.
1/1.8 mm
1/1.2 mm
1/2.24 mm
1/1.4 mm✔
The aluminum conductor of size 1.5 or 1 /1.40 mm (Number and diameter) will be used for a sub-circuit in the house wiring and minimum size of the conductor for power wiring is 4 mm2 or 1/2.24 mm (No. and diameter) may be used.
Ques 30. Two lamps, Green (G) and Red (R) are connected in a motor circuit as shown in fig. The conditions under which the lamps will burn are? (Supply is available at terminals A & B)
Green and red lamps burn when switch ‘S’ is closed.
Green lamp burns always, the red lamp burns only when switch ‘S’ is closed
The green lamp will not burn always, red lamp burns only when switch ‘S’ is closed.
The green lamp burns only when ‘S’ is open and the red lamp burns only when ‘S’ is closed.✔
The green lamp burns only when ‘S’ is open and red lamp burns only when ‘S’ is closed.
