### Computer Science - Electronic Principles MCQs Part 4

1. 1 Microfarad is the same as:

A.
B.
C.
D.
E.
None of the above

2. Which one of the following statements is true for resistance in a parallel circuit?

A.
The total resistance is equal to the sum of the individual resistances in a parallel circuit.
B.
The total resistance of a parallel circuit is always less than the value of the smallest resistance
C.
The total resistance of a parallel circuit is equal to the total voltage
D.
The total resistance in a parallel circuit is equal to the average value of the individual resistances
E.
None of the above

3. The direction of conventional current flow is:

A.
from negative to positive
B.
from positive to negative
C.
from left to right
D.
from neutral to positive
E.
None of the above

4. Doubling the operating frequency of a purely inductive circuit:

A.
doubles the amount of current through the inductors
B.
has no effect on the current through the inductors
C.
cuts the current through the inductors one-half
D.
increases the current, but by an amount that can be determined only by doing a complete analysis of the circuit
E.
None of the above

5. The secondary voltage for a certain power transformer is twice the voltage applied to the primary. The current flowing in the secondary winding will be:

A.
One-half the primary current
B.
Same as the primary current
C.
Twice the primary current
D.
No more than 10% less than the primary current
E.
None of the above

6. What is a free electron?

A. An electron that has been freed from its parent atom
B. An electron that costs nothing
C. An electron that has no electrical charge
D. An electron that has twice the amount of charge of a normal electron
E. None of the above

7. To get the Norton current, you have to

C. Short the voltage source
D. Open the voltage source
E. None of the above

8. The barrier potential accross each depletion layer is

A. 0
B. 0.8 V
C. 0.7 V
D. 20 V
E. None of the above

9. Which one of the following properties of a magnetic circuit can be directly compared to voltage in an electrical circuit?

A. Flux density
B. Number of lines of force
C. Magnetomotive force
D. Reluctance
E. None of the above

10. What kind of battery is most likely included in a cordless electric knife?

A. Zinc-carbon battery
B. Mercury-cell battery
E. None of the above

11. The basic unit of measurement for resistance is the:

A. volt
B. ampere
C. ohm
D. watt
E. None of the above

12. What is the phase shift between total current and voltage, if 100 ohm resistor connected in parallel with an inductor that has a reactance of 200W?

A. 0 degree
B. 26.6 degree
C. 90 degree
D. 180 degree
E. None of the above

13. When operating below its resonant frequency, a series RLC circuit has the characteristics of a:

A. series RL circuit
B. series RC circuit
C. series RLC circuit operated above its resonant frequency
D. purely resistive circuit
E. None of the above

14. The valence electron of a copper atom experiences what kind of attraction toward the nucleus?

A. Strong
B. Neutral
C. Weak
D. Impossible to say
E. None of the above

15. Suppose a step-down transformer has a turns ration of 5:1. If the secondary current is 1A rms, what is the primary-current?

A. 0.3 A
B. 0.2 A
C. 0.4 A
D. 0.6 A
E. None of the above

16. Absolute Zero temperature equals

A. 0o C
B. -273o C
C. -276o C
D. 25o C
E. None of the above

17. At cut off, the Q point is at

A. upper end of the load line
B. middle of the load line
C. lower end of the load line
D. infinity
E. None of the above

18. The south pole of a magnet is the one:

A. that would be attracted to the earths north magnetic pole
B. that has its molecules arranged in a random pattern
C. that would be attracted to the earth's south magnetic pole
D. that would be repelled by the north pole of another magnet
E. None of the above

19. Which one of the following statements is true?

A. Capacitive reactance is at a minimum for dc source voltages
B. Capacitive reactance decreases as the operating frequency increases
C. There is no meaningful relationship between capacitive reactance and operating frequency
D. Capacitive reactance increases as the operating frequency increases
E. None of the above

20. The peak value of a sine waveform is:

A. the amplitude at 70.7% of the maximum value
B. the amplitude at 90% of the maximum value
C. the amplitude at 1.41 times the maximum value
D. the maximum positive or negative value
E. None of the above

21. Which one of the following statements is true for voltage in a parallel circuit?

A. The total voltage in a parallel circuit is equal to the average value of the individual voltages
B. The total voltage in a parallel circuit is always less than the value of the smallest voltage
C. The total voltage is equal to the sum of the voltages across the individual branches in a parallel circuit
D. The total voltage of a parallel circuit is the same as the voltages across each branch
E. None of the above

22. The dielectric constant of a material is a measure of:

A. the amount of voltage it can withstand before breaking down
B. how well the material concentrates electrostatic lines of force
C. the amount of opposition to the current flow
D. how well the material concentrates magnetic lines of force
E. None of the above

23. What is the inductive reactance of a 2-H coil operating at 60 Hz?

A. 754 Ohm
B. 30 Ohm
C. 60 Ohm
D. 120 Ohm
E. None of the above

24. When operating above its resonant frequency, a series RLC circuit has the characteristics of a:

A. series RL circuit
B. series RC circuit
C. series RLC circuit operated below its resonant frequency
D. purely resistive circuit
E. None of the above

25. What is the primary difference between primary and secondary cell batteries?

A. Primary-cell batteries can be recharged and used many times, whereas secondary-cell batteries cannot be properly recharged
B. Secondary-cell batteries can be recharged and used many times, whereas primary-cell batteries cannot be properly recharged
C. Primary-cell batteries use chemical cells, whereas secondary-cell batteries use an alternative energy source, such as thermal or magnetic energy, to supplement their outputs
D. Primary-cell batteries must be recharged at a much slower rate that secondary-cell batteries
E. None of the above

26. Which one of the following statements applies to common auto batteries?

A. Auto batteries are primary wet-cell batteries
B. Auto batteries are secondary wet-cell batteries
C. Auto batteries are secondary dry-cell batteries
D. Auto batteries are primary dry-cell batteries
E. None of the above

27. Which one of the following equations most directly determines the power dissipation of a resistance when you know the power dissipation of a resistance when you know the voltage drop and current?

A. P = IE
B. P = E2/R
C. P = I2R
D. I = P/E
E. None of the above

28. If N1/N2 = 2, and the primary voltage is 120 V, what is the secondary voltage?

A. 0 V
B. 36 V
C. 40 V
D. 60 V
E. None of the above

29. A device that converts light energy to electrical energy is called a:

A. thermocouple
B. solar cell
C. photodiode
D. photo transistor
E. None of the above

30. How much current flows through a 60-W light bulb that is operating at 120 V?

A. 0.5A
B. 180 A
C. 2 A
D. 7200 A
E. None of the above

31. What is the power dissipation of a resistance that has 24 V dropped across it and 0.25 A flowing through it?

A. 3 W
B. 6 W
C. 64 W
D. 122 W
E. None of the above

32. Which one of the following kinds of materials has the highest permeability?

A. A diamagnetic material
B. A ferromagnetic material
C. A paramagnetic material
D. All of the above
E. None of the above

33. Inductive reactance is measured in units of:

A. volts per second
B. amperes per second
C. Ohm
D. henrys
E. None of the above

34. What is the difference between the kinds of charges for an electron and a proton?

A. An electron has a positive charge and a proton has no charge
B. An electron has a positive charge and a proton has a negative charge
C. An electron has a negative charge and a proton has a positive charge
D. An electron has a negative charge and a proton has no charge
E. None of the above

35. An ideal voltage source has

A. Zero internal resistance
B. Infinite internal resistance
E. None of the above

36. A transistor has how many doped regions?

A. 1
B. 2
C. 3
D. 4
E. None of the above

37. The voltage across a 1N4001 is 0.93V when the current is 1A. What is the power dissipation of the diode for these values?

A. 0.93 W
B. 0.93 V
C. 1 A
D. 9.3 W
E. None of the above

A. a natural magnet
B. a temporary magnet
C. an artificial magnet
D. a paramagnetic alloy
E. None of the above

39. Which one of the following phrases most accurately describes a purely capacitive circuit?

A. Resistances provide the only opposition to current flow
B. Capacitive reactance provides the only opposition to current flow
C. The ac voltage leads the current by 90 degree
D. Combinations of resistance and capacitive reactance provide any opposition to current flow
E. None of the above

40. The saturation point is approximately the same as

A. cutoff point
B. lower end of the load line
C. upper end of the load line
D. infinity
E. None of the above

41. Which one of the following statements is true for the currents in a series RC circuit?

A. The current always has the same amplitude and phase for every part of the circuit
B. The total current is equal to the sum of the currents for the resistance and capacitance
C. The total current is greater than the sum of the currents for the resistance and capacitance
D. The total current is less than the sum of the currents for the resistance and capacitance
E. None of the above

42. The total inductance of a series inductor circuit is:

A. equal to the sum of the individual inductance values
B. equal to the sum of the individual inductive-reactance values
C. less than the value of the smallest inductor
D. equal to the source voltage divided by total current
E. None of the above

43. Determine the resistance value and tolerance of a resistor that has the following color bands; first band is red, second band is red, third band is orange, and the fourth band is gold

A. 220 Ohm, 5%
B. 220 Ohm, 10%
C. 22,000 Ohm, 5%
D. 22, 000 Ohm, 10%
E. None of the above

44. Which one of the following is most likely used for measuring the rate of electron flow?

A. Voltmeter
B. Ammeter
C. Wattmeter
D. Ohmmeter
E. None of the above

45. Suppose a voltage source has an ideal voltage of 15V and a source resistance of 0.2W. For what values of load resistance will the voltage source appear stiff?

A. 20 Ohm
B. 30 Ohm
C. 10 Ohm
D. 100 Ohm
E. None of the above

46. Which one of the following statements regarding ac circuits is correct?

A. Current and voltages are in phase through a resistor
B. Current leads the voltage through a resistor
C. Current lags the voltage through a resistor
D. All of the above
E. None of the above

47. Which one of the following statements most accurately describes the nature of inductive reactance?

A. Inductive reactance is an opposition to current flow in dc circuits
B. Inductive reactance is an opposition to current flow in ac circuits
C. Inductive reactance is another term for counter emf
D. Inductive reactance is a force that tends to overcome the effects of counter emf
E. None of the above

48. What are the main parts of an atom?

A. Protons only
B. Electrons, protons, and ions
C. Electrons, ions, and neutrons
D. Electrons, protons, and neutrons
E. None of the above

49. Current is

A. The flow of charged particles through a material
B. An imbalance of electrical charges
C. The force that causes electrons to flow
D. The number of free electrons in an atom
E. None of the above

50. A real voltage source has

A. Zero internal resistance
B. Infinite internal resistance
C. A small internal resistance
D. A large internal resistance
E. None of the above