 Electronics Engineering Mastery Test 12: ECE Pre-Board

(Last Updated On: September 27, 2018) This is 100 items set of Practice Examination 12 in Electronics Engineering composed of previous and/or poterntial Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 5 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 12

Choose the letter of the best answer in each questions.

1. An advantage of an electromagnet over a permanent magnet is that:

• A. An electromagnet can be switched on and off
• B. An electromagnet does not have specific polarity
• C. An electromagnet requires no power source
• D. Permanent magnets must always be cylindrical

Solution:

2. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetized force is called

• A. Leftover magnetism
• B. Residual magnetism
• C. Hysteresis
• D. Coercivity

Solution:

3. Three resistors of 10, 15, and 20 Ω each are connected in parallel. What is the total conductance?

• A. 0.217 S
• B. 3.41 S
• C. 4.62 S
• D. 0.52 S

Solution:

4. What temperature in which the specific resistance of materials is usually measured?

• A. 290 K
• B. 300 K
• C. 20°C
• D. 0°C

Solution:

5. When one resistance in a series string is open, the

• A. current is maximum in the normal resistances
• B. current is zero in all of the resistances
• C. voltage is zero across the open resistance
• D. current increases in the voltage source

Solution:

6. The equivalent wye element of 3 equal resistors each equal to R and connected in delta is

• A. R
• B. 3R/2
• C. R/3
• D. 3R

Solution:

7. A lead storage battery is rated at 12 V. If the internal resistance is 0.01 Ω, what is the maximum power that can be delivered to the load?

• A. 1,200 W
• B. 7,200 W
• C. 3,600 W
• D. 1,800 W

Solution:

8. A simple circuit having a source of 7 nanovolts and a load of 3 kilo-mega ohms has a current equivalent to

• A. 23.33 amperes
• B. 2.333 attoamperes
• C. 2.333 amperes
• D. 2.333 deca amperes

Solution:

9. What happens to the flow of electrons in electronic circuit when the resistance is increased?

• A. The speed of flow will remain constant
• B. The flow become faster
• C. The flow will be decreased
• D. No flow will occur

Solution:

10. A circuit contains an inductor of 10 H in series with the capacitor of 0.001 F and operating at a frequency of 4 MHz. What is the net reactance or X in MΩ?

• A. 2.4727
• B. 2472.7
• C. 247.27
• D. 24.727

Solution:

11. What is the relationship between frequency and the value of R?

• A. R varies indirectly
• B. R varies indirectly
• C. Frequency has no effect
• D. R varies directly

Solution:

12. Longest life cell capable of 20, 000 times charged-discharged cycle and could last 30 years or over

• B. Lithium cell
• C. Nickel hydrogen
• D. Alkaline cell

Solution:

13. It is considered to be a negative charge of electricity?

• A. Atom
• B. Electron
• C. Neutron
• D. Proton

Solution:

14. Refers to a field surrounding electrons and protons at stationary period indicating a stored energy

• A. Magnetic field
• B. Electrostatic field
• C. Electron field
• D. Electrodynamic field

Solution:

15. The time required to complete one complete cycle of a waveform

• A. Crest
• B. Wavelength
• C. Frequency
• D. Period

Solution:

16. Lines of flux generated by one winding which do not link the other winding

• A. Flux loss
• B. Leakage flux
• C. Reactance leakage
• D. Inductance leakage

Solution:

17. What determines whether a substance is an insulator or a conductor?

• A. Number of protons
• B. Number of Photons
• C. Number of valence electrons
• D. Number of neutrons

Solution:

18. Which of the following is positive electricity?

• A. Resinous dynamic electricity
• B. Vitreous dynamic electricity
• C. Vitreous static electricity
• D. Resinous static electricity

Solution:

19. If the magnitude of the potential difference is generated by a single conductor passing through a magnetic field, which of the following statements is FALSE?

• A. The potential difference depends on the speed with which the conductor cuts the magnetic field
• B. The potential difference depends on the length of the conductor that cuts the magnetic field
• C. The potential difference depends on the magnetic field density that is present
• D. The potential difference depends on the diameter of the conductor that cuts the magnetic field

Solution:

20. A current of 10-A flows through a 1 mm diameter wire. What is the average number of electrons that pass through a cross section of the wire per second?

• A. 1.6 x 1018 e/s
• B. 6.2 x 1018 e/s
• C. 1.6 x 1019 e/s
• D. 6.3 x 1019 e/s

Solution:

21. Which of the following statements is true for steady-state conditions in a circuit powered by a dry a cell?

• A. Voltage is dependent upon time
• B. Capacitors behave as short circuits
• C. Inductors behave as short circuits
• D. Resistors behave as open circuits

Solution:

22. What is the internal resistance of a 9 V battery that delivers 100 A when its terminals are shorted?

• A. 0.09 Ω
• B. 11 Ω
• C. 1.0 Ω
• D. 90 Ω

Solution:

23. The change in the direction of a compass needle, when a current-carrying wire is brought near, is:

• A. Electromagnetic deflection
• B. Electrostatic force
• C. Magnetic force
• D. Electroscopic force

Solution:

24. Suppose a certain current in a galvanometer causes the needle to deflect 20 degrees, and then this current is doubled. The needle deflection:

• A. Will decrease
• B. Will stay the same
• C. Will increase
• D. Will reverse direction

Solution:

25. A unidirectional form of DC can be derived from which of the following sources?

• A. Battery
• B. Generator
• C. Rectifier circuits
• D. Power supply

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