MCQ in Electrical Circuit Part 9 | ECE Board Exam

(Last Updated On: October 3, 2018)

This is the Multiples Choice Questions Part 9 of the Series in Electrical Circuit as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in AC-DC circuits
• MCQ in Resistors
• MCQ in Inductors
• MCQ in Capacitors

Continue Practice Exam Test Questions Part 9 of the Series

Choose the letter of the best answer in each questions.

401. A 100-volt source is supplying a parallel RC circuit having a total impedance of 35.35 Ω. Calculate the total line current.

A. 2.83 ∠ 45°

B. 2.83 ∠ -45°

C. 4.00 ∠ 45°

D. 4.00 ∠ -45°

402. What is the power factor of a circuit if the inductive susceptance and conductance have the same value?

A. 0.325

B. 0.525

C. 0.673

D. 0.707

403. If a circuit has an admittance of Y = 0.2 + j0.6, the circuit is

A. purely inductive

B. inductive

C. capacitive

D. reactive

404. The circuit admittance Y = 0.2 – j0.6, the circuit is

A. resistive

B. inductive

C. capacitive

D. reactive

405. What is the resonant frequency of a circuit when L is 50 microhenrys and C is 40 picofarads are in parallel?

A. 7.96 MHz

B. 79.6 MHz

C. 3.56 MHz

D. 1.78 MHz

406. If you need an LC circuit to be resonant at 2500 Hz and use a 150 mH coil, what should the capacitance value be?

A. 0.027 μF

B. 0.015 μF

C. 0.15 μF

D. 27 μF

407. What is the resonant frequency of a circuit when L of 3 microhenry and C of 40 picofarad are in series?

A. 1.33 MHz

B. 14.5 MHz

C. 14.5 kHz

D. 1.33 kHz

408. What is the resonant frequency of a circuit when L of 25 microhenry and C of 10 picofarad are in parallel?

A. 63.7 MHz

B. 10.1 MHz

C. 63.7 kHz

D. 10.1 kHz

409. A series circuit at resonance would mean, the circuit is

A. resistive

B. inductive

C. capacitive

D. reactive

410. Characteristics of the current in a series R-L-C circuit at resonance.

A. It is dc

B. It is a minimum

C. It is zero

D. It is at maximum

411. What is the cause of a minimum Q on a single-tuned LC circuit?

A. decreased series resistor

B. decreased shunt resistor

C. increased shunt resistor

D. decreased capacitance

412. Find the half-power bandwidth of a parallel resonant circuit, which has a resonant frequency of 3.6 MHz and a Q of 218.

A. 606 kHz

B. 58.7 kHz

C. 16.5 kHz

D. 47.3 kHz

413. A parallel circuit at resonance would mean, the circuit is

A. resistive

B. inductive

C. reactive

D. capacitive

414. What will happen to a parallel ac-circuit if its line frequency is more than the resonant frequency?

A. becomes purely resistive

B. becomes purely capacitive

C. becomes inductive

D. becomes capacitive

415. In a series ac-circuit, if the line frequency is more than the resonant frequency, the circuit behaves as

A. resistive

B. inductive

C. reactive

D. capacitive

416. If the line frequency of a parallel ac-circuit is less than the resonant frequency, the circuit behaves as

A. resistive

B. reactive

C. capacitive

D. purely inductive

417. If an ac-series circuit is supplied with a source whose frequency is less than that of fr, the circuit becomes

A. resistive

B. reactive

C. inductive

D. capacitive

418. _________ is a parallel LC circuit.

A. Parallel resisting circuit

B. Static circuit

C. Tank circuit

D. Hartley circuit

419. A parallel LC network with L = 100 mH and C = 25 μF will resonate at what frequency?

A. 25 Hz

B. 45.5 Hz

C. 75.6 Hz

D. 100 Hz

420. Absolutely, when can we say that the circuit is at resonance?

A. when XL = XC

B. when the current is minimum

C. when the voltage and current are in-phase

D. all of the above

421. The description of two sine waves that are in step with each other going through their maximum and minimum points ate the same time and in the same direction.

A. Sine waves in phase

B. Stepped sine waves

C. Phased sine waves

D. Sine waves in coordination

422. Term used for the out of phase, non-productive power associated with inductors and capacitors.

A. Effective power

B. True power

C. Reactive power

D. Peak envelope power

423. Refers to a reactive power.

A. Wattles, non productive power

B. Power consumed in circuit Q

C. Power loss because of capacitor leakage

D. Power consumed in wire resistance in an inductor

424. A 240 V, 25 Hz sinusoidal generator is connected to a 20 ohms resistor. Determine the instantaneous current when elapsed time is 0.01 second.

A. 15043A

B. 16.30 A

C. 16.97 A

D. 12.00 A

425. The product of current and voltage in an AC circuit refers to the

A. Real power

B. Useful power

C. Apparent power

D. DC power

426. The distance covered or traveled by a waveform during the time interval of one complete cycle.

A. Frequency

B. Wavelength

C. Time slot

D. Wave time

427. The power dissipated across the resistance in an AC circuit.

A. Real power

B. Reactive power

C. Apparent power

D. True power

428. It is the number of complete cycles of alternating voltage or current complete each second

A. Period

B. Frequency

C. Amplitude

D. Phase

429. How many degrees are there in one complete cycle?

A. 720 deg

B. 360 deg

C. 180 deg

D. 90 deg

430. The impedance in the study of electronics is represented by resistance and _________ .

A. Reactance

B. Inductance and capacitance

C. Inductance

D. capacitance

431. Two current sources deliver to a common load. The first source delivers current whose equation is 25sin 100πt A while the second delivers a current whose equation is 15 cos 100πt A. What is the rms values of the current in the load?

A. 29.15 A

B. 40 A

C. 20.6 A

D. 10 A

432. It is a rotating sector that represent either current or voltage in an AC circuit.

A. Resistance

B. Phasor

C. polar diagram

D. velocity

433. The relationship of the voltage across an inductor to its current is described as

A. Leading the current by 90 deg

B. Lagging the current by 90 deg

C. Leading the current by 180 deg

D. In phase with the current

434. Find the phase angle between the voltage across through the circuit when X_c is 25 ohms, R is 100 ohms and X_L is 50 ohms.

A. 76 deg with the voltage leading the current

B. 24 deg with the voltage lagging the current

C. 14 deg with the voltage leading the current

D. 76 deg with the voltage lagging the current

435. Calculate the period of an alternating current having a equation of I=20sin 120πt

A. 4.167 ms

B. 8.33 ms

C. 16.67 ms

D. 33.33 ms

436. What do you mean by root-mean-square (rms) value?

A. It is the average value

B. It is the effective value

C. It is the value that causes the same heating effect as the DC voltage

D. b or c

437. The maximum instances value of a varying current, voltage or power equal to 1.414 times the effective value of a sine wave.

A. RMS value

B. Peak value

C. Effective value

D. Peak to Peak value

438. If an AC signal has a peak voltage of 55 V, what is the average value?

A. 35 V

B. 61.05V

C. 86.34 V

D. 38.89 V

439. If an AC signal has an average voltage of 18 V, what is the rms voltage?

A. 12.726 V

B. 19.980 V

C. 25.380 V

D. 16.213 V

440. A 220-V, 60Hz is driving a series R_L circuit. Determine the current if R = 100 ohms and 20 mH inductance

A. 2.2 A (lagging)

B. 2.0 A (lagging)

C. 2.2 A (leading)

D. 2.0 A (leading)

441. Ignoring any inductive effects, what is the impedance of RC series capacitor made up of a 56K ohm resistor and a 0.33 uF capacitor at a signal frequency of 4650 Hz.

A. 66730 ohms

B. 57019 ohms

C. 45270 ohms

D. 10730 ohms

442.What is the time constant of a 500 mH coil and a 3300 ohm resistor in series?

A. 0.00015 sec

B. 6.6 sec

C. 0.0015 sec

D. 0.0000015 sec

443. What is the relationship between frequency and the value of X_C ?

A. Frequency has no effect

B. XC varies inversely with frequency

C. XC varies indirectly with frequency

D. XC varies directly with frequency

444. The reactance of a 25 mH coil at 5000 Hz which of the following?

A. 785 ohms

B. 785000 ohms

C. 13 ohms

D. 0.0012 ohms

445. There are no transients in pure resistive circuits because they

A. Offer high resistance

B. Obey ohm’s Law

C. Are linear circuits

D. Have no stored energy

446. The reciprocal of capacitance is called

A. Conductance

B. Elastance

C. Permitivity

D. permeability

447. The AC system is preferred over DC system because

A. Ac voltages can easily changed in magnitude

B. Dc motors do not have fine speed control

C. High voltage AC transmission is less efficient

D. DC voltage cannot be used for domestic appliances

448. An alternating voltage is given by v = 20 sin 157 t. The frequency of the alternating voltage is

A. 50 Hz

B. 25 HZ

C. 100 Hz

D. 75 Hz

449. An alternating current given by i = 10 sin 314 t. The time taken to generate two cycles of current is

A. 20 ms

B. 10 ms

C. 40 ms

D. 50 ms

450. In a pure resistive circuit, the instantaneous voltage and are current are given by:

v = 250sin314t i = 10sin314t

The peak power in the circuit is

A.1250 W

B. 25 W

C. 2500 W

D. 250 w

Questions and Answers in Electrical Circuit

Following is the list of practice exam test questions in this brand new series:

Complete List of MCQ in Electronics Engineering per topic