Current Electricity Class 12 NCERT Solutions – Physics Chapter 3

Quick Navigation – Jump to Question

NCERT Solutions Class 12 Physics Chapter 3 – Current Electricity

3.1

Q1 Class 12 Physics problem on potential energy of a charge system-Current Electricity NCERT Solutions
Q1 step-by-step solution to calculate potential energy of charge system-Current Electricity NCERT Solutions

3.2

Q2 question on calculating work done in assembling a system of charges-Current Electricity NCERT Solutions
Q2 calculation of total work done arranging point charges-Current Electricity NCERT Solutions

3.3

Q3 capacitor energy stored in presence of dielectric material-Current Electricity NCERT Solutions

Ans – Based on the above problem, we all know that the given element at room temperature would be (T = 27.0 C), and the overall resistance of the heating element tends to be 100 Ω (say R).
Additionally, the temperature coefficient of the heating component can be represented as α = 1.70 × 10−4 C−1.
In the vicinity of a higher temperature (let’s say T1), the heating element’s resistivity tends to be 117 Ω (let’s say R1). The mathematical equation for a material’s temperature coefficient may have been employed to determine this unidentified elevated temperature T1. It has become well known that a substance’s temperature coefficient explains something about the chemical composition of the substance regarding the range of resistance varying according to drastic temperature changes.
In terms of arithmetic concepts, the above statement can be represented as,

Q3 capacitor energy derived using dielectric constant and voltage-Current Electricity NCERT Solutions

3.4

Q4 potential distribution in uniformly charged spherical shell-Current Electricity NCERT Solutions

Ans – From the above question, it’s been intimated that:
The total length of the wire substance is l = 15m
The cross-sectional area of the wire element would be, a = 6.0×10−7 m2
Resistance of the wire material available can be denoted as, R = 5.0 Ω
Let us assume that the resistivity of the wire-based material stays at ρ
We all know that the resistance is seamlessly linked to the overall resistivity of the substance. Hence,

Q4 electric potential derived for spherical shell interior and exterior-Current Electricity NCERT Solutions

3.5

Q5 Class 12 question on potential inside a charged conductor
Q5 potential at various points in and outside charged conductor

Assume that silver’s coefficient of temperature is represented as α. It has become well known that a substance’s temperature coefficient tells us something about the chemical composition of the substance based on how the resistant mechanism operates & exhibits its potential based on the constant temperature change. In mathematical terminology, it’s been linked to both temperature & resistance based on the below technique:

Q5 simplified conclusion showing uniform internal potential

3.6

Q6 calculation of charge stored in multi-plate capacitor
Q6 multi-plate capacitor charge calculated using equivalent capacitance
Q6 final boxed value of charge stored in capacitor

3.7

Q7 numerical involving change in capacitance with dielectric insertion

Ans – The current passing through the different branches of the circuit is illustrated in the given figure.

Q7 capacitance change due to dielectric slab inserted between plates
Q7 final value with dielectric effect considered

3.8

Q8 question on loss in energy when plates are disconnected from battery
Q8 energy loss derived when battery is disconnected from capacitor

A series resistor in a charging circuit is responsible for regulating the current drawn from the external source. Omitting this series resistor poses a significant risk, as the current flow would become excessively high in that scenario.

3.9

Q9 NCERT-based problem on change in electric field and energy stored
Q9 electric field and energy variation calculated post dielectric removal

Class 12 Physics Chapter 3 – Current Electricity Overview

Electricity runs almost everything in our lives, thus every science student has to know how electric current flows. In this chapter, you’ll learn about how charges migrate via conductors, Ohm’s law, drift velocity, and how resistors act in different circuit setups. Our Current Electricity NCERT Solutions break down each theory in a way that students can understand, making even Kirchhoff’s laws seem easy to understand and use.

Students typically have trouble using theory to solve problems, especially when resistors are put together in complicated circuits or when internal resistance and emf are involved. These solutions are helpful since they not only explain each step thoroughly, but they also teach you how to get around board tests quickly and easily. Because of this, you’ll feel more confident and better at answering things that used to be hard for you.

The 2025 NCERT curriculum update put more emphasis on real-world uses, such as power transmission, the thermal effects of current, and I–V graphs that ask conceptual issues. Also, unnecessary derivations have been cut down to make way for assignments that test your skills and questions on circuit analysis. Our Current Electricity NCERT Solutions are completely in line with these revisions, so you won’t miss anything important for your tests.

In conclusion, these answers give you clarity, organization, and regular reinforcement of important concepts, whether you’re getting ready for board exams, the JEE, or just trying to figure out how to charge your phone. If you keep practicing, even the hardest issues will start to make sense. That’s why these chapter-by-chapter solutions are a must-have for your study plan.

FAQs – Current Electricity Class 12 Chapter-3 NCERT

Why do I keep confusing emf and terminal voltage?

That’s common! emf is the source voltage without any current flow. However, terminal voltage drops when current flows due to internal resistance.

How do I know when to apply Kirchhoff’s laws?

Whenever you’re dealing with loops or multiple junctions, Kirchhoff’s laws are your best tools. The solutions use labeled circuits to teach current flow step-by-step.

Why do I get stuck on series-parallel resistance questions?

These are tricky at first. That’s why we included decision charts and solved examples that guide you through resistor combinations like a flowchart.

What’s new in the 2025 NCERT syllabus for this chapter?

It now emphasizes graphical interpretations, power loss in transmission, and real-life circuit analysis. Therefore, practice with graph-based and reasoning-based problems is essential.

I always forget units and make calculation errors—any advice?

Don’t worry! Each solution includes unit checks and hints on common mistakes to avoid during board exams and mocks.