In this article, we shared the ohms law objective questions and answers for electrical and electronics engineers.

## Ohms Law Objective Questions

The below list provides all the multiple-choice questions related to basics and examples of problems on ohms law.

Answers are available at the bottom of the article.

**1. **A closed switch has a resistance of

A) | zero |

B) | about 50 ohms |

C) | infinity |

D) | about 500 ohms |

**2. **The resistance of a few meters of wire conductor in a closed electrical circuit is

A) | low |

B) | practically zero |

C) | very high |

D) | high |

**3. **For which of the following substances the temperature coefficient of resistivity is positive?

A) | Electrolyte |

B) | Germanium |

C) | Carbon |

D) | Aluminium |

**4. **Which of the following materials has the least resistivity?

A) | Zinc |

B) | Copper |

C) | Mercury |

D) | Lead |

**5. **The resistance of a copper wire 200 m long is 21 ω.

If its thickness (diameter) is 0.44 mm, its specific resistance is around

A) | 1.2 x 10^{-8} ω-m |

B) | 1.4 x 10^{-8} ω-m |

C) | 1.8 x 10^{-8} ω-m |

D) | 1.6 x 10^{-8} ω-m |

**6. **Temperature coefficient of resistance is expressed in terms of

A) | ohms/ohm°C |

B) | mhos/ohm°C |

C) | mhos/°C |

D) | ohms/°C |

**7. **Specific resistance of a conductor depends upon

A) | dimensions of the conductor and composition of conductor material. |

B) | dimensions of the conductor. |

C) | composition of conductor material. |

D) | resistance of the conductor |

**8. **Heat in a conductor is produced on the passage of electric current due to

A) | reactance |

B) | capacitance |

C) | impedance |

D) | resistance |

**9. **Which resistor will be physically larger in size?

A) | 10ω, 50W |

B) | 1kω, 1W |

C) | 1Mω, 1/2W |

D) | 100ω, 10W |

**10. **A light bulb draws 300 mA when the voltage across it is 240 V.

The resistance of the light bulb is

A) | 800 ω |

B) | 600 ω |

C) | 400 ω |

D) | 1000 ω |

**11. **A 3 ω resistor having 2 A current will dissipate the power of

A) | 6 watts |

B) | 8 watts |

C) | 2 watts |

D) | 4 watts |

**12. **With rise in temperature the resistance of semiconductors

A) | decreases |

B) | increases |

C) | remains constant |

D) | first increases and then decreases |

**13. **Voltage dependent resistors are usually made from

A) | graphite |

B) | charcoal |

C) | nichrome |

D) | silicon carbide |

**14. **For determining the polarity of the voltage drop across a resistor, it is necessary to know the

A) | value of emf in the circuit. |

B) | value of current. |

C) | direction of current flowing through the resistor. |

D) | value of resistor. |

**15. **Three resistances of 10 ohms, 15 ohms, and 30 ohms are connected in parallel.

The total resistance of the combination is

A) | 10 ohms |

B) | 55 ohms |

C) | 15 ohms |

D) | 5 ohms |

**16. **Which of the following materials possesses the least specific resistance?

A) | Iron. |

B) | Aluminium. |

C) | Silver. |

D) | Copper. |

**17. **The temperature coefficient of resistance of an insulator is

A) | positive and independent of temperature. |

B) | positive and dependent on temperature |

C) | negative and dependent on temperature. |

D) | negative and independent of temperature. |

**18. **Two resistors R1 and R2 give combined resistance of 4.5 ω when in series and 1 ω when in parallel, the resistances are

A) | 4 ω and 0.5 ω |

B) | 1.5 ω and 3 ω |

C) | 1 ω and 3.5 ω |

D) | 2 ω and 2.5 ω |

**19. **Conductance is reciprocal of

A) | resistance |

B) | reluctance |

C) | capacitance |

D) | inductance |

**20. **If the length of a wire of resistance R is uniformly stretched to n times its original value, its new resistance is

A) | n R |

B) | R/n |

C) | n^{2}R |

D) | R/n^{2} |

**21. **Four wires of same material, the same cross-sectional area and the same length when connected in parallel give a resistance of 0.25 ω.

If the same four wires are connected is series the effective resistance will be

A) | 4 ω |

B) | 2 ω |

C) | 1 ω |

D) | 3 ω |

**22. **Voltage dependent resistors are used

A) | to supress surges |

B) | for inductive circuits |

C) | as heating elements |

D) | as current stabilizers |

**23. **The resistance of a parallel circuit consisting of two branches is 12 ohms.

If the resistance of one branch is 18 ohms, what is the resistance of the other?

A) | 36 ω |

B) | 64 ω |

C) | 48 ω |

D) | 18 ω |

**24. **In a series circuit with unequal resistances

A) | the lowest resistance has the highest current |

B) | In a series circuit with unequal resistances |

C) | the lowest resistance has the highest voltage drop |

D) | the highest resistance has the highest voltage drop |

**25. **Two resistances R1 and R2 are connected in series across the voltage source where R2 > R1. The largest drop will be across

A) | either R1 or R2 |

B) | R2 |

C) | none of these answers |

D) | R1 |

**26. **If a wire conductor of 0.2 ohm resistance is doubled in length, its resistance becomes

A) | 0.4 ohm |

B) | 1.0 ohm |

C) | 0.8 ohm |

D) | 0.6 ohm |

**27. **A network consists of linear resistors and ideal voltage source.

If the value of the resistors are doubled, then voltage across each resistor is

A) | not changed. |

B) | halved. |

C) | doubled. |

D) | increased four lines. |

**28. **The specific resistance of all metals is most affected by

A) | Degree of illumination |

B) | Applied magnetic field |

C) | Temperature |

D) | Pressure |

**29. **A resistance having rating 10 ohms, 10 W is likely to be a

A) | wire wound resistor |

B) | metallic resistor |

C) | variable resistor |

D) | carbon resistor |

**30. **Four resistances 80 ω, 50 ω, 25 ω and R are connected in parallel.

Current through 25 ω resistance is 4 A.

Total current of the supply is 10 A.

The value of R will be

A) | 40.25 ω |

B) | 76.56 ω |

C) | 66.66 ω |

D) | 36.36 ω |

**31. **A rheostat differs from a potentiometer in the respect that it

A) | has lower wattage rating |

B) | has higher wattage rating |

C) | offers large number of tappings |

D) | has large number of turns |

**32. **Two resistors are said to be connected in series when

A) | both carry the same value of current |

B) | total current equals the sum of branch currents |

C) | same current passes in turn through both |

D) | sum of IR drops equals the applied e.m.f. |

**33. **Which of the following statements is correct regarding resistance?

A) | The resistance of a conductor is the hindrance by which the conductor opposes the flow of current through it. |

B) | The resistance of a wire does not depend upon its material. |

C) | The resistance of wire is independent of the temperature for most of the materials |

D) | None of these answers |

**34. **With three resistances connected in parallel, if each dissipates 20 W the total power supplied by the voltage source equals

A) | 40 W |

B) | 60 W |

C) | 10 W |

D) | 20 W |

**35. **A thermistor has

A) | negative temperature coefficient |

B) | zero temperature coefficient |

C) | positive temperature coefficient |

D) | variable temperature coefficient |

**36. **Specific resistance of a substance is measured in

A) | ωm^{2} |

B) | ω-m |

C) | m/ω |

D) | ω/m |

**37. **The resistance of two wires is 25 ω when connected in series and 6 ω when joined in parallel. The resistance of each wire is

A) | 10 ω, 15 ω |

B) | 20 ω, 30 ω |

C) | 5 ω, 10 ω |

D) | 10 ω, 20 ω |

**38. **With rise in temperature the resistance of pure metals

A) | decreases |

B) | remains constant |

C) | increases |

D) | first increases and then decreases |

**39. **Resistance of a wire always increases if

A) | temperature is reduced. |

B) | number of free electrons available become more. |

C) | number of free electrons available become less. |

D) | temperature is increased. |

**40. **Varistors are

A) | insulators |

B) | non-linear resistors |

C) | carbon resistors |

D) | resistors with zero temperature coefficient |

**41. **In equal resistances are first connected in series and then connected in parallel.

What is the ratio of the maximum to the minimum resistance?

A) | n^{2} |

B) | n |

C) | 1/n |

D) | 1/n^{2} |

**42. **Resistance of material always decreases if

A) | temperature of material is decreased |

B) | temperature of material is increased |

C) | none of these answers |

D) | number of free electrons available become more |

**43. **The resistance of a straight conductor does not depend upon its

A) | Length |

B) | Material |

C) | Shape of cross-section |

D) | Temperature |

**44. **In a circuit containing two unequal resistors connected in parallel

A) | The voltage drop is larger across larger resistances |

B) | The voltage drop is same across both the resistances |

C) | The current is larger in larger resistance |

D) | The current is same in both the resistors |

**45. **The specific resistance of a wire depends upon

A) | Its dimensions |

B) | Its length |

C) | Its cross-sectional area |

D) | Its material |

**46. **The temperature coefficient of resistance of a wire is 0.0008°C.

If the resistance of the wire is 8 ohm at 0°C, what is the resistance at 100°C?

A) | 8.08 Ohm. |

B) | 7.92 Ohm. |

C) | 8.64 Ohm. |

D) | 7.20 Ohm |

**47. **A current of 16 amperes divides between two branches in parallel of resistances 8 ohms and 12ohms respectively.

The current in each branch is

A) | 4.6A,9.6A |

B) | 6.4 A, 6.9 A |

C) | 4.6A, 6.9A |

D) | 6.4 A, 9.6 A |

**48. **In an ordinary heater if the length of the coil is halved, then a given quantity of water will boil

A) | More time |

B) | None of these answers |

C) | Less time |

D) | Same time |

**49. **Twelve 1 ω resistance are used as edges to form a cube.

The resistance between two diagonally opposite corners of the cube is

A) | 6/5 ω |

B) | 1 ω |

C) | 5/6 ω |

D) | 3/2 ω |

**50. **Which of the following is an ohmic conductor?

A) | Thermionic valves |

B) | Constanton |

C) | Electrolyte |

D) | Transistors |

**51. **Which of the following quantities remain the same in all parts of a series circuit?

A) | Resistance |

B) | Current |

C) | Voltage |

D) | Power |

**52. **You have to replace 1500 ω resistor in radio. You have no 1500 ω resistor but have several 1000 ω ones which you would connect

A) | two in parallel and one in series |

B) | three in parallel |

C) | three in series |

D) | two in parallel |

**53. **An open resistor, when checked with an ohm-meter reads

A) | high but within tolerance |

B) | zero |

C) | low but not zero |

D) | infinite |

**54. **Two copper conductors have equal length.

The cross-sectional area of one conductor is four times that of the other.

If the conductor having smaller cross-sectional area has a resistance of 40 ohms the resistance of other conductors will be

A) | 20 ohms |

B) | 160 ohms |

C) | 80 ohms |

D) | 10 ohms |

**55. **The insulation resistance of a cable of length 10 km is 1 Mega Ohm’s.

For a length of 100 km of same cable, the insulation resistance will be

A) | 1 Mega Ohm |

B) | 0.1 Mega Ohm |

C) | 10 Mega Ohm |

D) | 0.01 Mega Ohm |

**56. **The temperature coefficient of resistance of some material is negative. The material is

A) | Germanium |

B) | Iron |

C) | Aluminium |

D) | Copper |

**57. **The temperature coefficient of resistance of conductors is

A) | Neutral |

B) | Negative |

C) | none of these answers |

D) | Positive |

**58. **Three resistances each of R Ω are corrected to form a triangle. The resistance between any two terminals will be

A) | 3/2 R Ω |

B) | 3 R Ω |

C) | 2/3 R Ω |

D) | R Ω |

**59. **In a circuit a 33 ω resistor carries a current of 2 A. The voltage across the resistor is

A) | 66V |

B) | 132V |

C) | 33V |

D) | 80 V |

**60. **The example of non-ohmic resistance is

A) | Carbon resistance |

B) | Copper wire |

C) | Diode |

D) | Tungsten wire |

**61. **Reciprocal of specific resistance is

A) | Conductive resistance |

B) | Specific conductance |

C) | Plate resistance |

D) | Conductive reactance |

**62. **The resistance of a conductor varies inversely as

A) | temperature |

B) | resistivity |

C) | area of cross-section |

D) | length |

**63. **How are 500 ω resistors connected so as to give an effective resistance of 750ω?

A) | Three resistors of 500 ω each, in series. |

B) | Two resistors of 500 ω each, in parallel and the combination in series with another 500 ω resistor. |

C) | Three resistors of 500 ω each, in parallel |

D) | Two resistors of 500 ω each, in parallel. |

**64. **Three parallel resistive branches are connected across a dc supply.

What will be the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio R1 : R2 : R3 : : 2 : 4 : 6 ?

A) | 2 : 4 : 6 |

B) | 3 : 2 : 6 |

C) | 6 : 2 : 4 |

D) | 6 : 3 : 2 |

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