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

capacitor?

⦁ Paper

⦁ Mica

⦁

**Air**
⦁ Electrolyte

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

⦁ Polar

⦁

**Rectangular**
⦁ Trigonometric

⦁ Exponential

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

⦁ Inductive

⦁ Conductive

⦁ Resistive

⦁

**Capacitive**
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

˚C

⦁

**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**
⦁ Twice

⦁ 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?

⦁

**Zero**
⦁ 1.3 kfi

⦁ 628 fi

⦁ -628 fi

21 Barium-strontium titanite dielectric material is also called

⦁

**Ceramic**
⦁ Polyster

⦁ Electrolytic

⦁ Bakelite

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

⦁ Inductance

⦁ Conductance

⦁ Impedance

⦁

**Resistance**
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

⦁ Sawtooth

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

⦁ Infinite

⦁ Zero

⦁ Unequal

⦁

**Equal**
35 The current is times the maximum current at half-power points of a resonance

curve.

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

⦁ Dielectric

⦁ 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?

⦁

**Zero**
⦁ Infinity

⦁ k fi

⦁ M fi

43 Points to be considered in choosing a capacitor

⦁ Working voltage

⦁ Type of dielectric

⦁ Capacitance

⦁

**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?

⦁

**Volt-ampere**
⦁ Joule

⦁ Watt-second

⦁ Volt-coulomb

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

⦁ Short-circuiting

49 Which component opposes voltage change?

⦁ Resistor

⦁ Inductor

⦁

**Capacitor**
⦁ Transistor

50 What is the peak factor for alternating current or voltage varying sinusiodally?

⦁

**1.4142**
⦁ 0.707

⦁ 0.636

⦁ 1.11

No comments:

Post a Comment