ELECTRICAL CIRCUITS Multiple Choice Questions Part 2

ELECTRICAL CIRCUITS Multiple Choice Questions Part 2

ELECTRICAL CIRCUITS Multiple Choice Questions Part 2.

1 A capacitor of 0.5 µF charged to 220 V is connected across an uncharged 0.5 µF capacitor. What is the voltage across each capacitor?
220 V
150 V
110 V
22 V

2 When capacitors are connected in series, the total capacitance is
Smaller than the smallest capacitor
Smaller than the largest capacitor
Greater than any of the capacitor
Greater than the largest capacitor

3 What theorem is generally used in the analysis of vacuum tubes?
Superposition theorem
Millman’s theorem
Thevenin’s theorem
Norton’s theorem

4 The ratio between the reactive power and the apparent power of an ac load is called
Quality factor
Power factor
Power ratio
Reactive power

5 What is the efficiency under the conditions of maximum power transfer?
A.    50 %
B.    100 %
C.    25 %
D.    75 %

6 The charging of a capacitor through a resistance follows what law?
Linear law
Hyperbolic law
Inverse-square law
Exponential law

7 Which of the following is the peakiest?
Square wave
Sinusoidal wave
Triangular wave
Rectangular wave

8 Why are inductance and capacitance not relevant in a dc circuit?
Because it is a simple circuit
Because dc circuits require only resistance as load
Because they do not exist in a dc circuit
Because frequency of dc is zero

9 When capacitors are connected in parallel, the total capacitance is
Greater than the largest capacitor
Smaller than the largest capacitor
Smaller than the smallest capacitor
Greater than the smallest capacitor

10 A switch designed to have low capacitance between its terminal when open.
LOCAP switch
AntiLOCAP switch
Anticapacitance switch
Capacitance switch

11 A resistor wound with a wire doubled back on itself to reduce the inductance.
Bifilar resistor
Wire-wound resistor
Anti-inductive resistor
Bleeder resistor

12 Which of the following dielectric materials makes the lowest-capacitance

13 In adding or subtracting phasor quantities, form is the most convenient.

14 An impedance given by 90²-45˚ is a/an impedance.

15 If a coil has a Q of 10, it means that
The energy stored in the magnetic field of the coil is 10 times the energy wasted in its resistance
The energy wasted in its resistance is 10 times the energy stored in the magnetic field
of the coil
It is a low Q coil
It is a high Q coil

16 A lead conductor has a resistance of 25 fi at 0 ˚C. Determine its resistance at -30
22 fi
24 fi
12 fi
11 fi

17 What is the rms value of a square wave?
Equals its peak value
Equals its peak-to-peak value
Peak divided by square root of two
Peak divided by pi

18 When two coils of identical reactance are in parallel without mutual inductance, the reactance of the combination is the reactance of each coil.
One half
Four times
One fourth

19 Which of the following is also known as anti-resonant circuit?
Parallel resonant circuit
Series resonant circuit
Tuned circuit
Tank circuit

20 An inductor carries 2 A dc. If its inductance is 100 µH, then what is its inductive reactance?
1.3 kfi
628 fi
-628 fi

21 Barium-strontium titanite dielectric material is also called

22 The mutual inductance between two coils is the reluctance of magnetic path.
Directly proportional to
Inversely proportional to
Independent to
Equal to

23 The result of rust in electrical (wire) connection is

24 When the power factor of a circuit is zero,
Power absorbed is maximum
Power absorbed is minimum
Power absorbed is zero
The impedance is minimum

25 How many degrees of phase represents one full cycle?
A.    360
B.    180
C.    270
D.    90

26 Which of the following does not generally affect the value of a capacitor?
The dielectric material used
The surface area of the plates
The thickness of the dielectric
The voltage applied to the plate

27 What is the purpose of a load in an electric circuit?
To increase the circuit current
To decrease the circuit current
To utilize electrical energy
To make the circuit complete

28 What maximum voltage can be applied across the capacitor for very short period
of time?
Working voltage
Surge voltage
Stray voltage
Peak voltage

29 What is expected when two 20 kfi, 1 watt resistor in parallel are use instead of  one 10 kfi, 1 watt?
Provides higher current
Provides less power
Provides more power
Provides wider tolerance

30 Which waveform in which the rms value and the mean value are equal?
Square wave
Triangular wave
Sine wave

31 In a series circuit with unequal resistances the
Highest R has the highest V
Lowest R has the highest V
Lowest R has the highest I
Highest R has the highest I

32 In a parallel bank with unequal branch resistances
The highest R has the highest I
The lowest R has the highest V
The lowest R has the highest V
The highest R has the highest V

33 A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in series, the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.
Child’s law
CR law
Coulomb’s law
Debye T3 law

34 At parallel resonance, the currents flowing through L and C are

35 The current is times the maximum current at half-power points of a resonance
A.    0.707
B.    1.414
C.    0.5
D.    0.632

36 A gang capacitor is a variable capacitor in which capacitance is varied by changing the
Number of plates
Plate area
Distance between plates

37 What is the specific resistance of a pure germanium?
55 fi-cm
55 fi-m
55 fi-mm
55 kfi-m

38 Two capacitors of capacitance 9 µF and 18 µF in series will have a total capacitance of
27 µF
162 µF
6 µF
180 µF

39 As applied to a series RLC circuit, bandwidth means
The frequency range for maximum power transfer
The difference between the highest and lowest frequencies of the oscillator
The separation of the half-power points
The frequency at which XL = XC

40 If a capacitor is rated for 200V dc, what is its effective ac working voltage?
50 V
100 V
200 V
400 V

41 An open inductor has
Zero resistance and infinite inductance
Infinite resistance and zero inductance
Infinite resistance and infinite inductance
Zero resistance and zero inductance

42 What is the reading of an ohmmeter for a shorted capacitor?
k fi
M fi

43 Points to be considered in choosing a capacitor
Working voltage
Type of dielectric
All of the above

44 Permeability is otherwise known as
Magnetic conductivity
Magnetic susceptibility
Electric conductivity
Electric susceptibility

45 A trigger circuit consisting of a capacitor of 0.01 µF is connected in series with a resistor. If the circuit requires 100 Vdc to operate, determine the value of the resistor when time constant is 0.009s.
900 fi
900 kfi
900 Mfi
900 Gfi

46 Which of the following does not refer to electrical energy?

47 In an ac circuit with XL and R in series, the
Voltages across R and XL are in phase
Voltage across R lags the voltage across XL by 90°
Voltages across R and XL are 180° out-of-phase
Voltage across R leads the voltage across XL by 90°

48 Leakage resistance in a capacitor results into
Internal heating
Internal bleeding
Shorter useful life

49 Which component opposes voltage change?

50 What is the peak factor for alternating current or voltage varying sinusiodally?
⦁      1.4142
⦁      0.707
⦁      0.636
⦁      1.11

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