MCQOPTIONS
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MCQOPTIONS
This section includes 231 Mcqs, each offering curated multiple-choice questions to sharpen your Computer Science knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A transistor has a current gain of 125 and a base current of 30 µA. What is the collector current? |
| A. | 3.75 mA |
| B. | 3.2 mA |
| C. | 0.05 mA |
| D. | 13 mA |
| E. | None of the above |
| Answer» B. 3.2 mA | |
| 2. |
If N1/N2 = 2, and theprimary voltage is 120 V, what is the secondary voltage? |
| A. | V |
| B. | 6 V |
| C. | 0 V |
| D. | 0 V |
| E. | one of the above |
| Answer» E. one of the above | |
| 3. |
Whichisthemost widelyused semiconductor? |
| A. | opper |
| B. | ilicon |
| C. | ermanium |
| D. | ll of the above |
| E. | one of the above |
| Answer» C. ermanium | |
| 4. |
Thekneevoltageof adiodeis approximately equal to the |
| A. | pplied voltage |
| B. | arrier potential |
| C. | reakdown voltage |
| D. | orward voltage |
| E. | one of the above |
| Answer» C. reakdown voltage | |
| 5. |
The period of a waveform is: |
| A. | 1000 V |
| B. | 100 mV |
| C. | 1000 mV |
| D. | None of the above |
| Answer» B. 100 mV | |
| 6. |
Which one of the following statements is true for the currents in a parallel RL circuit? |
| A. | is contant |
| B. | varies slightly |
| C. | equals the collector current divided by the base current |
| D. | None of the above |
| Answer» D. None of the above | |
| 7. |
What is one important thing transistors do? |
| A. | Emit light |
| B. | Amplify weak signals |
| C. | Regulate voltage |
| D. | Rectify line voltage |
| Answer» C. Regulate voltage | |
| 8. |
The emitter diode is usually |
| A. | Forward-biased |
| B. | Reverse-biased |
| C. | Nonconducting |
| D. | Operating in the breakdwon region |
| Answer» B. Reverse-biased | |
| 9. |
The primary impedance of a transformer is 60 ohm and the secondary impedance is 120 ohm. What is the impedance ratio? |
| A. | 0.25 |
| B. | 180 |
| C. | 0.5 |
| D. | 4 |
| Answer» D. 4 | |
| 10. |
Which one of the following devices is most often used for measuring electrical potential difference? |
| A. | Voltmeter |
| B. | Ohmmeter |
| C. | Ammeter |
| D. | Wattmeter |
| Answer» B. Ohmmeter | |
| 11. |
Which one of the following properties of a magnetic circuit can be directly compared to current in an electrical circuit? |
| A. | Number of lines of force |
| B. | Flux density |
| C. | Reluctance |
| D. | Magnetomotive force |
| Answer» B. Flux density | |
| 12. |
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 |
| Answer» D. Impossible to say | |
| 13. |
A real voltage source has |
| A. | Zero internal resistance |
| B. | Infinite internal resistance |
| C. | A small internal resistance |
| D. | A large internal resistance |
| Answer» D. A large internal resistance | |
| 14. |
What is the difference between a conductor and an insulator? |
| A. | A conductor allows current to flow much easier than an insulator does |
| B. | An insulator has an excessive number of free electrons, while a conductor has a few free electrons or none at all |
| C. | An insulator allows current to flow much easier than a conductor does |
| D. | The difference between conductors and insulators depends on how they are used |
| Answer» B. An insulator has an excessive number of free electrons, while a conductor has a few free electrons or none at all | |
| 15. |
A circuit has two different voltage sources that are connected in a series-aiding form. If the sources are rated at 6 V and 9 V, what is the total source voltage? |
| A. | 15 V |
| B. | 16 V |
| C. | 7.5 V |
| D. | 8 V |
| Answer» B. 16 V | |
| 16. |
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 |
| Answer» D. An electron has a negative charge and a proton has no charge | |
| 17. |
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 |
| Answer» C. The ac voltage leads the current by 90 degree | |
| 18. |
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 |
| Answer» C. the amount of opposition to the current flow | |
| 19. |
At room temperature an intrinsic semiconductor has |
| A. | a few free electrons and holes |
| B. | many holes |
| C. | many free electrons |
| D. | No holes |
| Answer» B. many holes | |
| 20. |
How many protons does the nucleus of a silicon atom contain? |
| A. | 4 |
| B. | 29 |
| C. | 14 |
| D. | 48 |
| Answer» D. 48 | |
| 21. |
Inductive reactance is measured in units of: |
| A. | volts per second |
| B. | amperes per second |
| C. | Ohm |
| D. | henrys |
| Answer» D. henrys | |
| 22. |
Current and voltage are said to be in phase when: |
| A. | their waveforms are both ac or both dc |
| B. | they have the same amplitude and frequency |
| C. | their waveforms cross through zero and reach positive and negative peaks at the same time |
| D. | All of the above |
| Answer» D. All of the above | |
| 23. |
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 |
| Answer» B. P = E2/R | |
| 24. |
A resistor has a rated value of 100 ohm and a tolerance of 10%. What is its minimum and maximum allowable resistance value? |
| A. | 90 Ohm - 101 ohm |
| B. | 90 Ohm - 110 ohm |
| C. | 98 Ohm - 100.1 ohm |
| D. | 99 Ohm - 102 ohm |
| Answer» C. 98 Ohm - 100.1 ohm | |
| 25. |
How much power is being dissipated by a 1000 W resistance that has 25 V applied to it? |
| A. | 0.24 W |
| B. | 0.625 W |
| C. | 80 W |
| D. | 325 kW |
| Answer» C. 80 W | |
| 26. |
At room temperature an intrinsic silicon crystal acts approximately like |
| A. | a battery |
| B. | a conductor |
| C. | an insulator |
| D. | a piece of copper wire |
| Answer» D. a piece of copper wire | |
| 27. |
Norton's theorem replaces a complicated circuit facing a load by an |
| A. | Ideal voltage source and parallel resistor |
| B. | Ideal current source and parallel resistor |
| C. | Ideal voltage source and series resistor |
| D. | Ideal current source and series resistor |
| Answer» C. Ideal voltage source and series resistor | |
| 28. |
The graph of current gain versus collector current indicates that the current gain |
| A. | varies enormously |
| B. | is contant |
| C. | varies slightly |
| D. | equals the collector current divided by the base current |
| Answer» E. | |
| 29. |
The equivalent of 1 megohms is: |
| A. | 1 k ohm |
| B. | 100,000 ohm |
| C. | one-millionth of an ohm |
| D. | one million ohms |
| Answer» E. | |
| 30. |
A device that converts thermal energy to electrical energy is called a: |
| A. | thermocouple |
| B. | solar cell |
| C. | chemical cell |
| D. | piezoelectric devices |
| Answer» B. solar cell | |
| 31. |
The equivalent of 1 kV is: |
| A. | 1.00 V |
| B. | 1000 V |
| C. | 100 mV |
| D. | 1000 mV |
| Answer» C. 100 mV | |
| 32. |
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 |
| Answer» E. | |
| 33. |
The transistor has a current gain of 175. If the base current is 0.1 mA, what is the collector current? |
| A. | 1750 mA |
| B. | 17.5 mA |
| C. | 175 mA |
| D. | 1.75 mA |
| Answer» C. 175 mA | |
| 34. |
The transistor has a collector current of 2 mA. If the current gain is 135, what is the base current? |
| A. | 14.8 µA |
| B. | 10.3 µA |
| C. | 7.8 µA |
| D. | 7.75 µA |
| Answer» B. 10.3 ¬µA | |
| 35. |
Two diodes are in series. The first diode has a voltage of 0.75 V and the second has a voltage of 0.8 V. If the current through the first diode is 500 mA, what is the current through the second diode |
| A. | 11 mA |
| B. | 12 mA |
| C. | 10 mA |
| D. | 14 mA |
| Answer» D. 14 mA | |
| 36. |
Which one of the following is a statement of KirchhofFs voltage law? |
| A. | The total voltage in a parallel circuit is less than the value of the smallest voltage |
| B. | The algebraic sum of voltages in a loop is equal to zero |
| C. | The voltage drop across a resistance is proportional to the value of resistance and the amount of current flowing through it |
| D. | The algebraic sum of voltages entering and leaving a point is equal to zero |
| Answer» C. The voltage drop across a resistance is proportional to the value of resistance and the amount of current flowing through it | |
| 37. |
A current source has an internal resistance of 100 kW. What is the largest load resistance if the current source must appear stiff? |
| A. | 2 k Ohm |
| B. | 10 k Ohm |
| C. | 20 k Ohm |
| D. | 1 k Ohm |
| Answer» E. | |
| 38. |
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 |
| Answer» B. 30 Ohm | |
| 39. |
A device that converts mechanical pressure to electrical energy is called a: |
| A. | piezoelectric device |
| B. | solar cell |
| C. | photodiode |
| D. | nicad cell |
| Answer» B. solar cell | |
| 40. |
The total capacitive reactance of a parallel capacitor circuit is: |
| A. | equal to the sum of the individual capacitive-reactance values |
| B. | equal to the sum of the individual capacitance values |
| C. | equal to the source voltage divided by total current |
| D. | less than the capacitance value of the smallest capacitor |
| Answer» D. less than the capacitance value of the smallest capacitor | |
| 41. |
What is the total resistance of a parallel circuit that contains two resistors having values of 220 ohm and 470 ohm? |
| A. | 220 ohm |
| B. | 150 ohm |
| C. | 445 ohm |
| D. | 690 ohm |
| Answer» C. 445 ohm | |
| 42. |
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 |
| Answer» D. that would be repelled by the north pole of another magnet | |
| 43. |
An ideal voltage source has |
| A. | Zero internal resistance |
| B. | Infinite internal resistance |
| C. | A load dependent voltage |
| D. | A load-dependent current |
| Answer» B. Infinite internal resistance | |
| 44. |
The nucleus of the copper atom contains how many protons? |
| A. | 1 |
| B. | 4 |
| C. | 18 |
| D. | 29 |
| Answer» E. | |
| 45. |
If a transistor operates at the middle of the load line, an increase in the current gain will move the Q point |
| A. | down |
| B. | up |
| C. | nowhere |
| D. | off the load line |
| Answer» C. nowhere | |
| 46. |
A circuit has two different voltage sources that are connected in a series-opposing form. If the sources are rated at 6 V and 9 V, what is the total source voltage? |
| A. | 3 V |
| B. | 16 V |
| C. | 7.5 V |
| D. | 8 V |
| Answer» B. 16 V | |
| 47. |
Assuming 100% efficiency, what is the power being applied to the primary winding of the transformer described in the above question? |
| A. | 200 W |
| B. | 1000 W |
| C. | 20 W |
| D. | 100 W |
| Answer» B. 1000 W | |
| 48. |
Positive ions are atoms that have |
| A. | Gained a proton |
| B. | Lost a proton |
| C. | Gained an electron |
| D. | Lost an electron |
| Answer» E. | |
| 49. |
The total impedance of a series RLC circuit: |
| A. | is minimum at the resonant frequency |
| B. | always increases as the applied frequency increases |
| C. | always decreases as the applied frequency increases |
| D. | is maximum at the resonant frequency |
| Answer» B. always increases as the applied frequency increases | |
| 50. |
A diode is in series with 220W. If the voltage across the resister is 4V, what is the current through the diode? |
| A. | 55 A |
| B. | 55.86 A |
| C. | 18.2 mA |
| D. | 16.3 mA |
| Answer» D. 16.3 mA | |