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Free download in PDF Electric Circuits Objective Type Questions & Answers for competitive exams. These short objective type questions with answers are very important for competitive exams like IIT-JEE, NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries.
(1)
A resistor is connected across a 45 volt battery to provides 13 mA of current. The required resistance with suitable wattage rating will be
[A]
4.5 ohms, 1 watt
[B]
45 ohms, 10 watts
[C]
1000 ohms, 2 watts
[D]
45,000 ohms, 1/3 watt
Answer: 45,000 ohms, 1/3 watt
(22)
The formation of the hydrogen bubbles around the carbon electrode in a dry cell is
[A]
Local action caused by chemical impurities
[B]
Polarization caused by electrolysis
[C]
Depolarization caused by manganese dioxide
[D]
An advantage because it increases the voltage output
Answer: Polarization caused by electrolysis
(23)
The Edison cell
[A]
Is a primary cell
[B]
Uses sulphuric acid electrolyte
[C]
Has 2.5 volts output
[D]
Has nickel and iron electrolyte
Answer: Has nickel and iron electrolyte
(24)
A 45-volt source with an internal resistance of 2 ohms is connected across a wire-wound resistor. The maximum power will be dissipated in the resistor when its resistance equals
[A]
Zero
[B]
Ohms
[C]
45 ohms
[D]
Infinity
(25)
If the wire which is vertical to this page has electron flow downward the conductor will have
[A]
No magnetic field
[B]
A counter-clockwise field in the plane of the power
[C]
A clockwise field in the plane of the paper
[D]
A counter-clockwise field in the plane perpendicular to the paper
Answer: A counter-clockwise field in the plane of the power
(26)
A solenoid is a coil which
[A]
Acts as bar magnet only when there is no current in the conductor
[B]
Acts as bar magnet only when the current flows in the coil
[C]
Is similar to ring magnet because there is no air gap
[D]
Acts as bar magnet only when it has iron core
Answer: Acts as bar magnet only when the current flows in the coil
(27)
Motor action in a wire conducting current can be produced
[A]
Without any additional magnetic field
[B]
Move the conductor from weaker field toward stronger field
[C]
Move the conductor from stronger field toward a weaker field
[D]
Produce the motion of the conductor but not rotation
Answer: Move the conductor from stronger field toward a weaker field
(28)
Which of the following can produce maximum induced voltage?
[A]
1-amp. D.c. current
[B]
50-amp. D.c. current
[C]
1-amp. 60 cycles a.c. current
[D]
1-amp. 490 cycles a.c. current
Answer: 1-amp. 490 cycles a.c. current
(29)
An alternating current can induce voltage because it has
[A]
High r.m.s. value
[B]
Varying magnetic field
[C]
Stronger field than direct current
[D]
Constant magnetic field
Answer: Varying magnetic field
(30)
The d.c. resistance of a coil made with 100ft of gauge No. 30 copper wire is approximately
[A]
Less than one ohm
[B]
10.5 ohms
[C]
104 ohms
[D]
More than 1 M Ω
31
Inductive resistance is measured in ohms because it
[A]
Reduces the amplitude of alternating current
[B]
Increases the amplitude of alternating current
[C]
Increases the amplitude of direct current
[D]
Has a back e.m.f. opposing the voltage output of a battery
Answer: Reduces the amplitude of alternating current
32
An arc across the switch opening an R-L circuit is a result is a result of the
[A]
Long time constant
[B]
Large self-induced voltage across the inductance
[C]
Source of the voltage caused by IR drop across the resistance
[D]
Low resistance of the open switch
Answer: Large self-induced voltage across the inductance
33
Alternating current in the inductance will produce maximum induced voltage when the current has its
[A]
Maximum value
[B]
Maximum change in magnetic field
[C]
Minimum change in magnetic field
[D]
0.707 × Peak
Answer: Maximum change in magnetic field
34
Which of the following statements is true?
[A]
Iron core has maximum eddy-current losses
[B]
Laminated iron core has minimum eddy-current losses
[C]
Power-iron core has the maximum eddy-current losses
[D]
Air core has the minimum eddy-current
Answer: Air core has the minimum eddy-current
35
Which of the following statements is true?
[A]
Ceramic capacitors must be connected in the correct polarity
[B]
Electrolytic capacitor must be connected in the correct polarity
[C]
Mica capacitors are available in capacitance value of 1 to 10 micro-farad
[D]
Air capacitors have a blackband to indicate the outside foil
Answer: Electrolytic capacitor must be connected in the correct polarity
36
The amount of capacitive reactance with higher frequencies
[A]
Decreases
[B]
Increases
[C]
Remains same for frequencies
[D]
Decreases as the voltage increases
37
In sine wave a.c. circuit with Xc and R in series, the
[A]
Voltages across R and Xc are in phase
[B]
Voltages across R and Xc are 180° out of phase
[C]
Voltages across R leads the voltages across Xc by 90°
[D]
Voltage across R lags the voltage across Xc by 90°
Answer: Voltages across R leads the voltages across Xc by 90°
38
In a series L-C circuit at the resonant frequency the
[A]
Current is minimum
[B]
Voltage across C is minimum
[C]
Impedance is maximum
[D]
Current is maximum
Answer: Current is maximum
39
A ferrite core has less eddy-current loss than an iron core because ferrites have
[A]
Low resistance
[B]
High resistance
[C]
Low permeability
[D]
High hysteresis
40
With stray capacitance of 10μF, the capacitive reactance at 160 MHz equals
[A]
10 ohms
[B]
160 ohms
[C]
100 ohms
[D]
1000 ohms
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