Class 12 Physics Chapter 3 MCQs, titled Current Electricity, covers the essential concepts related to electric current, Ohm’s law, resistance, and various other important aspects of electric circuits. Understanding the behavior of current, potential difference, and the relationship between voltage and resistance is crucial for solving complex problems in physics. In this article, we will explore key topics from Chapter 3 and provide 20 MCQs (Multiple-Choice Questions) to help students effectively prepare for exams.

Rbse Class 12 Physics Chapter 3 MCQs - Current Electricity

Key Topics in Current Electricity

Electric Current: Electric current is the rate of flow of charge through a conductor. It is measured in amperes (A) and can be calculated using the formula:[math]I=QtI = \frac{Q}{t}I=tQ[/math]where I is the current, Q is the charge, and t is the time.
Ohm’s Law: Ohm’s law states that the current passing through a conductor is directly proportional to the potential difference across it and inversely proportional to its resistance. Mathematically,V=IRwhere V is the potential difference, I is the current, and RRR is the resistance.
Resistance: Resistance is the opposition to the flow of electric current. It depends on factors such as the material of the conductor, its length, and its cross-sectional area. The resistance of a conductor is given by the formula: [math]R=ρLAR = \rho \frac{L}{A}R=ρALwhere ρ\rhoρ[/math] is the resistivity, L is the length of the conductor, and A is its cross-sectional area.
Resistivity: Resistivity is a property of the material that quantifies how strongly it opposes the flow of electric current. It is measured in ohm-meters.
Power in Electrical Circuits: The power consumed by an electrical device is given by:P=IVP = IVP=IVor using Ohm’s law,[math]P=I2R=V2RP = I^2R = \frac{V^2}{R}P=I2R=RV2[/math]where P is the power, I is the current, V is the voltage, and RRR is the resistance.
Combination of Resistors: Resistors can be connected in series or parallel.
- In Series: The total resistance is the sum of individual resistances. [math]Rtotal=R1+R2+…R_{\text{total}} = R_1 + R_2 + \dotsRtotal=R1+R2+…[/math]
- In Parallel: The total resistance is given by: 1 [math]Rtotal=1R1+1R2+…\frac{1}{R_{\text{total}}} = \frac{1}{R_1} + \frac{1}{R_2} + \dotsRtotal1=R11+R21+…[/math]
Kirchhoff’s Laws: Kirchhoff’s current law (KCL) states that the total current entering a junction is equal to the total current leaving it. Kirchhoff’s voltage law (KVL) states that the sum of potential differences (voltage) around any closed loop is zero.
Wheatstone Bridge: It is a circuit used to measure an unknown resistance by balancing two legs of a bridge circuit.

Class 12 Physics Chapter 3 MCQs 20 MCQs on Current Electricity (in English and Hindi)

Here are 20 MCQs based on Chapter 3: Current Electricity. Each question is provided in both English and Hindi to help students understand and practice the concepts.

1. What is the SI unit of electric current?

(a) Volt
(b) Ampere
(c) Coulomb
(d) Ohm

Answer: (b) Ampere

1. विद्युत धारा की SI इकाई क्या है?

(a) वोल्ट
(b) एम्पीयर
(c) कूलम्ब
(d) ओम

उत्तर: (b) एम्पीयर

2. The resistance of a conductor depends on:

(a) Length of the conductor
(b) Cross-sectional area of the conductor
(c) Material of the conductor
(d) All of the above

Answer: (d) All of the above

3. Ohm’s law states that:

(a) V=IRV = IRV=IR
(b) V=I/RV = I/RV=I/R
(c) V=I+RV = I + RV=I+R
(d) None of these

Answer: (a) V=IRV = IRV=IR

4. In a series combination of resistors, the total resistance is:

(a) Equal to the sum of individual resistances
(b) Less than the smallest resistance
(c) Inversely proportional to the sum of the resistances
(d) Independent of individual resistances

Answer: (a) Equal to the sum of individual resistances

5. Which of the following is the unit of resistance?

(a) Joule
(b) Watt
(c) Ohm
(d) Coulomb

Answer: (c) Ohm

6. The power consumed by an electric appliance is directly proportional to:

(a) Resistance
(b) Voltage
(c) Current
(d) Both (b) and (c)

Answer: (d) Both (b) and (c)

7. The resistivity of a material depends on:

(a) Temperature
(b) Material
(c) Both (a) and (b)
(d) None of these

Answer: (c) Both (a) and (b)

8. If the potential difference across a conductor is doubled, the current will:

(a) Double
(b) Become half
(c) Remain the same
(d) Quadruple

Answer: (a) Double

9. The equivalent resistance of two resistors connected in parallel is:

(a) Always greater than either of the two resistances
(b) Always less than either of the two resistances
(c) Equal to the sum of the two resistances
(d) Equal to the difference between the two resistances

Answer: (b) Always less than either of the two resistances

10. The electrical energy consumed by a device is given by:

11. The equivalent resistance of three resistors in series is:

(a) Less than the smallest resistor
(b) Equal to the sum of the resistances
(c) Equal to the product of the resistances
(d) Inversely proportional to the sum of the resistances

Answer: (b) Equal to the sum of the resistances

12. Kirchhoff’s current law states that:

(a) The sum of currents entering a junction is equal to the sum of currents leaving it
(b) The total current at a point is always zero
(c) The sum of the potential differences in a loop is always zero
(d) None of these

Answer: (a) The sum of currents entering a junction is equal to the sum of currents leaving it

13. The power dissipated by a resistor is proportional to:

(a) The square of the voltage
(b) The square of the current
(c) The product of current and voltage
(d) All of these

Answer: (b) The square of the current

14. Which of the following is the correct formula for the energy stored in a capacitor?

15. When two resistors are connected in parallel, the total resistance:

(a) Increases
(b) Decreases
(c) Remains the same
(d) Becomes zero

Answer: (b) Decreases

16. The total resistance in a circuit with resistors in parallel is:

(a) The sum of the resistances
(b) The product of the resistances
(c) Less than the smallest resistance
(d) Greater than the largest resistance

Answer: (c) Less than the smallest resistance

17. In a Wheatstone bridge, the unknown resistance is calculated when:

(a) The bridge is balanced
(b) The current flows through the galvanometer
(c) The power dissipated is maximum
(d) None of these

Answer: (a) The bridge is balanced

18. The drift velocity of electrons in a conductor is:

(a) Directly proportional to the applied electric field
(b) Inversely proportional to the resistance
(c) Zero at higher temperatures
(d) Independent of the current

Answer: (a) Directly proportional to the applied electric field

19. Which of the following is true for the relationship between current and voltage in an ohmic conductor?

(a) The current is directly proportional to voltage
(b) The current is inversely proportional to voltage
(c) The current is independent of voltage
(d) The current and voltage are not related

Answer: (a) The current is directly proportional to voltage

20. The electric power consumed by an electric device can be measured in:

(a) Joules
(b) Watts
(c) Volts
(d) Amperes

Answer: (b) Watts

Conclusion

By practicing these MCQs, students can deepen their understanding of Current Electricity and prepare effectively for exams. These questions cover the core concepts of electric current, Ohm’s law, resistance, and circuit laws, providing a strong foundation for further studies in physics. Regular practice and revision will help students perform well in their exams and enhance their conceptual clarity.

Rbse Class 12 Physics Chapter 3 MCQs – Current Electricity

Table of Contents

Key Topics in Current Electricity

Class 12 Physics Chapter 3 MCQs 20 MCQs on Current Electricity (in English and Hindi)

Conclusion

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