ELECTRICAL CIRCUITS Multiple Choice Questions Part 5.

1 For series capacitors, total charge is
The sum of individual charges
Equal to the charge of either capacitors
Equal to the product of the charges
The quotient of the charges

2 A wire of one kilometre length has a resistance of 20 fi. If the length is halved, then the new resistance is the original resistance.
Half
Twice
One-fourth
Three times

3 What is the total resistance of a two equal valued resistors in series?
The difference of both
The product of both
Twice as one
The sum of their reciprocals

4 The ratio of maximum value to the effective value of an alternating quantity is called
Form factor
Peak factor
Dynamic factor
Leakage factor

5 The reason why alternating current can induce voltage is
It has high peak value
It has a stronger magnetic field than direct current
It has a constant magnetic field
It has a varying magnetic field

6 When two unequal values of resistors are connected in parallel across a dc source,
greater current flows through the
Higher resistance
Lower resistance
Higher wattage resistance
Lower wattage resistance

7 Which of the following is a way of decreasing mutual inductance?
Moving the coils closer
Moving the coils apart
Decreasing the number of turns of either coil
Increasing the number of turns of either coil

8 The charging of a capacitor through a resistance obeys
Exponential law
Logarithmic law
Linear law
Square law

9 A capacitance of 0.05 µF equals.
⦁      0.05 x 106 F
⦁      0.05 x 10-6 F
⦁      0.05 x 10-12 F
⦁      0.05 x 1012 F

10 The factor 0.707 for converting peak to rms applies only to
Square waves
Triangle waves
Sawtooth waves
Sine waves

11 When two in-phase sine waves that have identical frequency and amplitude are added together, then the result is a sine wave with the amplitude of either.
Half
Twice
Four times
One-fourth

12 Tungsten filament of bulbs has a hot resistance higher than its cold resistance due to its temperature coefficient which is
Positive
Negative
Zero
Infinite

13 A term used to express the amount of electrical energy stored in electrostatic field.
Joules
Coulombs
Watts
Electron-volt

14 Which of the following capacitors is suitable for dc filter circuits?
Mica
Ceramic
Paper
Electrolytic

15 A series RL circuit has R of 10 fi and XL of 5 fi, its impedance in rectangular
form is given by
10 + j 5 fi
10 + j 10 fi
10 – j 5 fi
10 – j 10 fi

16 When frequency of an ac wave decreases, the value of XL in a coil
Approaches zero
Gets larger positively
Gets larger negatively
Stays constant

17 What is the reciprocal of capacitance?
Reluctance
Susceptance
Elastance
Conductance

18 The resistance of an insulator when its temperature is increased.
Decreases
Remains the same
Increases
Varies

19 The  wavelength  of  an   alternating   waveform  depends  upon  the of the variation.
Period
Number
Frequency
Amplitude

20 In a complex number 5 + j 10, 10 is called part.
Imaginary
Real
Conjugate
Integer

21 The presence of an electric current is made known by
Electric shock
Effects produced
Magnetic shock
Flashing

22 The reciprocal of a complex number is
A complex number
A real number
An imaginary number
A whole number

23 Which of the following has negative temperature coefficient?
Carbon
Nickel
Brass
Constantan

24 In dividing or multiplying phasor quantities_____form is used.
Polar
Rectangular
Trigonometric
Exponential

25 The capacitance of a capacitor is relative permittivity.
Directly proportional to
Inversely proportional to
Equal to
Inversely proportional to the square of

26 If a multiplate capacitor has 10 plates, each of area 10 cm2, then
10 capacitors will be in parallel
10 capacitors will be in series
9 capacitors will be in parallel
9 capacitors will be in series

27 A neon glow lamp used as a night light ionizes at approximately
70 V
80 V
90 V
100 V

28 What dielectric is generally employed by a variable capacitor?
Mica
Air
Electrolyte
Ceramic

29 If the inductance is decreased, the impedance of the circuit containing a resistor a
capacitor and an inductor connected in series to an ac source
Decreases
Increases
Decreases or increases
Decreases, increases or remains the same

30 When the movable plates of a gang capacitor completely overlap the fixed plates, the capacitance of the capacitor is
Halfway between maximum and minimum
Maximum
Minimum
Zero

31 When the temperature of copper wire is increased its resistance is
Increased
Decreased
Constant
Zero

32 A trimmer is a variable capacitor in which capacitance is varied by changing the
Number of plates
Dielectric
Distance between plates
Plate area

33 When current and voltage arte in phase in an ac circuit, the is equal to zero.
Resistance
Reactance
Inductance
Capacitance

34 Thevenin’s theorem is what form of an equivalent circuit?
Current
Voltage
Both current and voltage
Neither current nor voltage

35 When resistance are connected in parallel, the total resistance is
Less than the smallest resistance in the connection
Greater than the smallest resistance in the connection
Between the smallest and greatest resistance in the connection
Increasing and decreasing depending upon the supply voltage

36 The arc across a switch when it open an RL circuit is a result of the
Large self-induced voltage across L
Long time constant
Low resistance of the open switch
Surge of resistance

37 In an ac circuit with a resistive branch and an inductive branch in parallel, the
Voltage across the inductance leads the voltage across the resistance by 90°
Resistive branch current is 90° out of phase with the inductive branch current
Resistive and inductive branch currents have the same phase
Resistive and inductive branch currents are 180° out-of-phase

38 Voltage resonance means
Series resonance
Parallel resonance
Current magnification
Gain magnification

39 Which of the following is not a factor affecting dielectric strength?
Mass
Moisture content
Temperature
Thickness

40 A factor that states how much the resistance changes for a change in temperature?
Resistivity
Specific resistance
Coefficient of temperature change
Temperature coefficient of resistance

41 An alloy composed of 84 % copper, 12 % manganese and 4 % nickel.
Manganin
Constantan
Nichrome
German silver wire

42 In a rectangular wave, the peak factor is.
⦁      1.16
⦁      1.73
⦁      1.11
⦁      1.0

43 The ohmic value of a resistor with negative temperature coefficient
Increases with increasing temperature
Increase with decreasing temperature
Stays unchanged with temperature change
Stays unaffected even with increasing temperature

44 What is the form factor of a triangular wave?
⦁      1.16
⦁      1.11
⦁      1.73
⦁      1.41

45 In a multiple capacitor, the plate area is
Increased
The same
Decreased
Variable

46 What is the time constant for L of 240 mH in series with R of 20 fi?
12 ms
4.8 s
⦁      83.3 s
⦁      12 s

47 In an ac circuit, the power dissipated as heat depends on
Impedance
Capacitive reactance
Resistance
Inductive reactance

48 The power factor of a circuit is equal to
RZ
XC/Z
XL/Z
R/Z

49 What fusion of elements is without chemical action between them?
Mixture
Compound
Alloy
Ionization

50 In a circuit, a passive element is one which
Supplies energy