In Class 12 Physics Chapter 3, titled "Current Electricity," students are introduced to the core principles of electric current, including Ohm’s law, resistance, and the relationship between current and voltage in a conductor. This chapter covers essential topics such as resistance in series and parallel, electrical power, and different types of resistive materials, establishing a fundamental understanding of how electric circuits operate.
In this article, students can download PDFs featuring MCQs designed for CBSE, CUET, and state board exams. There is also a PDF compilation of 10 years of Previous Year Questions (subjective) from NCERT/CBSE, without solutions, offering students a comprehensive tool for mastering Chapter 3 concepts.
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NCERT Class 12 Physics Chapters
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1.
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The number of electrons flowing through a conductor per second is 3·3 × 1019. The current flowing through the conductor is:
(a) 2·0 A (b) 3·4 A (c) 4·8 A (d) 5·3 A
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2.
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The current in a device varies with time t as I = 6 t, where I is in mA and t is in s. The amount of charge that passes through the device during t= 0s to t = 3s is
(a) 10 mC (b) 18 mC (c) 27 mC (d) 54 mC
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3.
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For a metallic conductor, the correct representation of variation of resistance R with temperature T is:
(a)
 (b)  (c)  (d)  |
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4.
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The masses of two cylindrical wires of copper are in the ratio of 1 : 3 and their lengths are in the ratio of 5 : 3. The ratio of their resistances will be:
(a) 1 : 3 (b) 2 : 5 (c) 2 : 3 (d) 3 : 5
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1.
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A wire of length L0 has a resistance R0. It is gradually stretched till its length becomes 2 Lo.
(a) Plot a graph showing variation of its resistance R with its length l during stretching.
(b) What will be its resistance when its length becomes 2 Lo?
(CBSE 2020, 2M)
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2.
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A set of ‘n’ identical resistors, each of resistance ‘R’ when connected in series have an effective resistance ‘X’. When they are connected in parallel, their effective resistance becomes ‘Y’. Find out the product of X and Y.
(CBSE 2019, 2M)
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3.
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A potential difference V is applied across a conductor of length ℓ and cross-sectional area A. Briefly explain how the current density j in the conductor will be affected if
(a) the potential difference V is doubled,
(b) the conductor were gradually stretched to reduce its cross-sectional area to
 and then the same potential difference V is applied across it. (CBSE 2023, 3M)
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4.
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(a) Differentiate between electrical resistance and resistivity of a conductor.
(b) Two metallic rods, each of length L, area of cross A1 and A2, having resistivities ρ1 and ρ2 are connected in parallel across a d.c. battery. Obtain the expression for the effective resistivity of this combination.
(CBSE 2020, 3M)
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NCERT Science Subjects
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Unit Name |
Sub Areas of Chapter 3: Current Electricity |
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Current Electricity |
3.1 Introduction |
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3.2 Electric Current |
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3.3 Ohm's Law |
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3.4 Drift of Electrons and the Origin of Resistivity |
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3.5 Limitations of Ohm's Law |
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3.6 Resistivity of Various Materials |
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3.7 Temperature Dependence of Resistivity |
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3.8 Electrical Energy, Power |
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3.9 Combination of Resistors - Series and Parallel |
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3.10 Cells, EMF, and Internal Resistance |
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3.11 Cells in Series and Parallel |
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3.12 Kirchhoff's Laws |
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3.13 Wheatstone Bridge |
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3.14 Meter Bridge |
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3.15 Potentiometer |
In NCERT Class 12 Physics Chapter 3, 'Current Electricity,' students study electric currents, resistors, and conductors, learning about Ohm's law and circuit resistance. NCERT Class 12 Physics Chapter 3 provides crucial knowledge for understanding electrical circuits, integral to electronics and engineering.
The chapter also includes Kirchhoff’s laws and Wheatstone bridge principles, emphasizing the practical applications of circuit analysis. Mastery of NCERT Class 12 Physics Chapter 3 enables students to solve real-world circuit problems, laying the foundation for careers in engineering.
