MCQOPTIONS
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MCQOPTIONS
This section includes 77 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
What is the reciprocal of resistance of a material called? Give its unit. |
| A. | Conductance, ohm-1 |
| B. | Conductivity, ohm-1 m-1 |
| C. | Conductance, ohm-1 m-1 |
| D. | Conductivity, ohm-1 |
| Answer» B. Conductivity, ohm-1 m-1 | |
| 2. |
Identify the factor which does not depend on the resistance of a conductor. |
| A. | Nature of material |
| B. | Area of cross-section |
| C. | Length |
| D. | Viscosity |
| Answer» E. | |
| 3. |
Give the SI unit of current density and its dimensional formula. |
| A. | Am-2, [A1L-2] |
| B. | Am2, [A1L2] |
| C. | Am-1, [A1L-1] |
| D. | Am1, [A1L1] |
| Answer» B. Am2, [A1L2] | |
| 4. |
What is the reciprocal of resistivity of a material called? Give its unit. |
| A. | Conductance, ohm-1 |
| B. | Conductivity, ohm-1 m-1 |
| C. | Conductance, ohm-1 m-1 |
| D. | Conductivity, ohm-1 |
| Answer» C. Conductance, ohm-1 m-1 | |
| 5. |
Give the SI unit of resistivity. |
| A. | ohm/metre2 |
| B. | ohm metre2 |
| C. | ohm metre |
| D. | ohm/metre |
| Answer» D. ohm/metre | |
| 6. |
What is the approximate resistance setting of a rheostat in which 650 mA of current flows with a 150 V source? |
| A. | 9.7 Ω |
| B. | 97 Ω |
| C. | 23 Ω |
| D. | 230 Ω |
| Answer» E. | |
| 7. |
How much resistance is required to limit the current from a 12 V battery to 3.6 mA? |
| A. | 3.3 kΩ |
| B. | 33 kΩ |
| C. | 2.2 kΩ |
| D. | 22 kΩ |
| Answer» B. 33 kΩ | |
| 8. |
The formula to find I when the values of V and R are known is |
| A. | I = VR |
| B. | I = R/V |
| C. | V = IR |
| D. | I = V/R |
| Answer» E. | |
| 9. |
The current through a flashlight bulb is 40 mA and the total battery voltage is 4.5 V. The resistance of the bulb is approximately |
| A. | 112 Ω |
| B. | 11.2 Ω |
| C. | 1.2 Ω |
| D. | 18 Ω |
| Answer» B. 11.2 Ω | |
| 10. |
What is the voltage source for a circuit carrying 2 A of current through a 36 Ω resistor? |
| A. | 1.8 V |
| B. | 18 V |
| C. | 7.2 V |
| D. | 72 V |
| Answer» E. | |
| 11. |
You are measuring the current in a circuit that is operated on an 18 V battery. The ammeter reads 40 mA. Later you notice the current has dropped to 20 mA. How much has the voltage changed? |
| A. | 9 V |
| B. | 900 mV |
| C. | 0 V |
| D. | 18 V |
| Answer» B. 900 mV | |
| 12. |
Ohm's law describes how current is related to voltage and resistance. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 13. |
If 24 V are applied across a resistor and there are 10.9 mA of current, the resistance is |
| A. | 220 kΩ |
| B. | 22 kΩ |
| C. | 2.2 kΩ |
| D. | 220 Ω |
| Answer» D. 220 Ω | |
| 14. |
When 12 V are applied across a 68 Ω resistor, the current is |
| A. | 816 mA |
| B. | 17.6 mA |
| C. | 176 mA |
| D. | 8.16 mA |
| Answer» D. 8.16 mA | |
| 15. |
A 120 V lamp-dimming circuit is controlled by a rheostat and protected from excessive current by a 3 A fuse. To what minimum resistance value can the rheostat be set without blowing the fuse? Assume a lamp resistance of 20 ohms. |
| A. | 40 Ω |
| B. | 4 Ω |
| C. | 2 Ω |
| D. | 20 Ω |
| Answer» E. | |
| 16. |
When there is 12 mA of current through a 1.2 kΩ resistor, the voltage across the resistor is |
| A. | 14.4 V |
| B. | 1.4 V |
| C. | 100 V |
| D. | 10 V |
| Answer» B. 1.4 V | |
| 17. |
The formula for finding voltage when resistance and current are known is V = I/R. |
| A. | True |
| B. | False |
| Answer» C. | |
| 18. |
The formula for finding resistance when current and voltage are known is R = I/V. |
| A. | True |
| B. | False |
| Answer» C. | |
| 19. |
How much resistance is needed to draw 17.6 mA from a 12 volt source? |
| A. | 212 Ω |
| B. | 6.8 kΩ |
| C. | 68 Ω |
| D. | 680 Ω |
| Answer» E. | |
| 20. |
Twelve volts are applied across a resistor. A current of 3 mA is measured. What is the value of the resistor? |
| A. | 4 Ω |
| B. | 400 Ω |
| C. | 4 kΩ |
| D. | 4.4 Ω |
| Answer» D. 4.4 Ω | |
| 21. |
How much voltage is needed to produce 2.5 A of current through a 200 Ω resistor? |
| A. | 50 V |
| B. | 500 V |
| C. | 80 V |
| D. | 8 V |
| Answer» C. 80 V | |
| 22. |
A current of 200 µA through a 6.8 kΩ resistor produces a voltage drop of |
| A. | 34.4 V |
| B. | 340 V |
| C. | 13.6 V |
| D. | 1.36 V |
| Answer» E. | |
| 23. |
An electric heater draws 3.5 A from a 110 V source. The resistance of the heating element is approximately |
| A. | 385 Ω |
| B. | 38.5 Ω |
| C. | 3.1 Ω |
| D. | 31 Ω |
| Answer» E. | |
| 24. |
A resistance of 3.3 MO is connected across a 500 V source. The resulting current is approximately |
| A. | 15.1 µA |
| B. | 151 µA |
| C. | 66 mA |
| D. | 660 mA |
| Answer» C. 66 mA | |
| 25. |
What is the approximate resistance of a rheostat if the voltage source is 18 V and the current is 220 mA? |
| A. | 8.2 kΩ |
| B. | 820 Ω |
| C. | 8.2 Ω |
| D. | 82 Ω |
| Answer» E. | |
| 26. |
Approximately how much current flows through a 3.3 MO resistor across a 30 V source? |
| A. | 9 µA |
| B. | 90 µA |
| C. | 900 µA |
| D. | 9000 µA |
| Answer» B. 90 µA | |
| 27. |
According to Ohm's Law |
| A. | V is directly proportional to I |
| B. | V is inversely proportional to I |
| C. | V is directly proportional to vI |
| D. | All of the above |
| Answer» B. V is inversely proportional to I | |
| 28. |
If 750 µA is flowing through 11 kΩ of resistance, what is the voltage drop across the resistor? |
| A. | 8.25 V |
| B. | 82.5 V |
| C. | 14.6 V |
| D. | 146 V |
| Answer» B. 82.5 V | |
| 29. |
Approximately how many milli-amperes of current flow through a circuit with a 40 V source and 6.8 kΩ of resistance? |
| A. | 27.2 mA |
| B. | 59 mA |
| C. | 5.9 mA |
| D. | 590 mA |
| Answer» D. 590 mA | |
| 30. |
A resistor is connected across a 50 V source. What is the current in the resistor if the color code is red, orange and silver? |
| A. | 2 mA |
| B. | 2.2 mA |
| C. | 214 mA |
| D. | 21.4 mA |
| Answer» C. 214 mA | |
| 31. |
If you wish to increase the amount of current in a resistor from 120 mA to 160 mA by changing the 24 V source, what should the new voltage setting be? |
| A. | 8 V |
| B. | 320 V |
| C. | 3.2 V |
| D. | 32 V |
| Answer» E. | |
| 32. |
The ampere is the unit of resistance. |
| A. | True |
| B. | False |
| Answer» C. | |
| 33. |
Four amperes of current are measured through a 24 Ω resistor connected across a voltage source. How much voltage does the source produce? |
| A. | 960 V |
| B. | 9.6 V |
| C. | 96 V |
| D. | 8 V |
| Answer» D. 8 V | |
| 34. |
What is the approximate filament resistance of a light bulb if it operates from a 110 V source and 0.6 A of current is flowing? |
| A. | 183 Ω |
| B. | 18.3 Ω |
| C. | 66 Ω |
| D. | 6.6 Ω |
| Answer» B. 18.3 Ω | |
| 35. |
How much current is produced by a voltage of 18 kV across a 15 kΩ resistance? |
| A. | 1.2 A |
| B. | 12 A |
| C. | 120 mA |
| D. | 12 mA |
| Answer» B. 12 A | |
| 36. |
The current is ___ if the voltage across a 5 k resistor is 25 V. |
| A. | 200 mA |
| B. | 125 mA |
| C. | 75 mA |
| D. | 5 mA |
| Answer» E. | |
| 37. |
The power is ___ if 200 J of energy are used in 10 s. |
| A. | 2 W |
| B. | 5 W |
| C. | 20 W |
| D. | 50 W |
| Answer» D. 50 W | |
| 38. |
Power is a measure of how fast current is flowing. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 39. |
Resistance and current are _________. |
| A. | directly proportional |
| B. | inversely proportional |
| C. | not related |
| D. | similar to voltage |
| Answer» C. not related | |
| 40. |
If the current in the given circuit is increased to 24 mA, the source voltage must have tripled. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 41. |
The number of joules used in 1 second is always equal to the number of _______. |
| A. | siemens |
| B. | coulombs |
| C. | amperes |
| D. | watts |
| Answer» E. | |
| 42. |
The value of a resistor is in direct proportion to its power handling capabilities. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 43. |
Heat produced by a resistor is generally a desirable effect. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 44. |
The power rating for the resistor in the given circuit should be at least ______. |
| A. | 1/4 W |
| B. | 1/2 W |
| C. | 1 W |
| D. | 2 W |
| Answer» E. | |
| 45. |
Ohm's law describes the mathematical relationship between |
| A. | ohms, kilohms, and megohms |
| B. | resistor size and resistor value |
| C. | resistance, voltage, and current |
| D. | none of the above |
| Answer» D. none of the above | |
| 46. |
Doubling the voltage across a resistor will cut the current by half. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 47. |
Power supplies are regulated to prevent the output voltage from changing due to changes in the |
| A. | line voltage |
| B. | supply load |
| C. | frequency |
| D. | both line voltage and supply load |
| Answer» E. | |
| 48. |
___ is a better way of expressing 7,500,000 W. |
| A. | 7.5 kW |
| B. | 7,500 MW |
| C. | 7,500 GW |
| D. | 7.5 MW |
| Answer» E. | |
| 49. |
The voltage supplying the current in the given circuit is _____. |
| A. | 2.5 V |
| B. | 25 V |
| C. | 250 V |
| D. | 2.5 kV |
| Answer» C. 250 V | |
| 50. |
The voltage drop across a resistor is simply a difference of potential across that resistor. |
| A. | 1 |
| B. | |
| Answer» B. | |