# DC Pandey Current Electricity Solutions

DC Pandey Electricity and Magnetism Solutions Chapter 20 ‘Current Electricity’ will provide you with the basic guide to gain clarity in the concepts of current electricity. The topics covered in this chapter include an introduction to electric current and resistance, ohm’s law. You will also learn about the dependence of resistivity and resistance on temperature. Other scoring topics from this chapter include the electromotive force, Kirchhoff’s law, the heating and chemical effect of current, measuring instruments, and thermoelectricity.

There are 198 questions in the DC Pandey Physics Book Solutions Current Electricity chapter. These questions are divided into 3 sets of exercises and are arranged at different levels according to the increasing order of complexity of the questions. These exercises will provide you with ample opportunity to practice the topics rigorously. There is a wide variety of questions from numerical problems to assertion-reasoning problems. These exercises will help you in preparing for your entrance exams like JEE Mains and JEE Advanced extensively as you will get an idea about the pattern of questions asked in these exams.

The Instasolv experts have designed the set of solutions for DC Pandey Current Electricity in a systematic format. These solutions are based on the latest DC Pandey Physics syllabus for Class 11 and Class 12 will help you cover the entire chapter with complete conceptual understanding through a step by step answer to each question. We, at Instasolv, have made an attempt to make sure that you get the answers to all the doubts that might arise while practising the questions in DC Pandey Electricity and Magnetism Solutions.

## Important Topics for DC Pandey Electricity and Magnetism Solutions Chapter 20: Current Electricity

**Electric Current**

If we ensure a directed flow of the electric charge through the cross-section of an electric conductor, this directed rate of flow is termed as the electric current. If the charge flowing is qin time t, then current in the current will be given as:

where e is the value of charge while n is the total number of electrons.

Current is a scalar quantity and its direction is given parallelly in the direction of flow of positive charge. If we assume that the flow of current is perpendicular to the cross-sectional area of the conductor then the ratio of current flowing at a given point to the area of cross-section gives the current density at that point in the cross-section. Note that it is a vector quantity and is denoted by J.

**Resistance and Ohm’s Law**

According to Ohm’s Law, the electric current passing through an electrical conductor is in proportion with the potential difference across the end-points of the conductor.

The proportionality constant is termed as resistance and denoted by R. Therefore, Ohm’s law states, V= IR where V is the potential difference and I is the measure of current.

**Temperature Dependence of Resistance and Resistivity**

Resistivity is the resistance offered to the flow of electric current by a conductor having a unit cross-sectional area and the measure of its length as 1 unit. It can be expressed mathematically as,

The SI unit is ohm denoted by Ω.

The resistivity of a given material is a function of the temperature of the material given as:

T=o1-T-To such that Tand o are resistivities at the given and at a reference temperatures T and T0and is the temperature coefficient of resistivity.

**Electromotive Force**

When we develop a potential difference between the ends of a given conductor with the help of an electrochemical cell or by varying the magnetic field between them, the force that develops is termed as Electromotive Force or emf. It can be given mathematically as,

=V + Ir

Where ‘V’ is the potential difference in the cell

‘I’ gives the electric current in the circuit

And r represents the internal resistance of the cell.

**Kirchhoff’s Law**

There are two Kirchhoff’s Laws that deal with the conservation of energy in a circuit.

- Kirchhoff’s First Law: No charge at a junction is lost. Total current coming in at a node is equal to the total current leaving the node.
- Kirchhoff’s Second Law: The total of all the voltage drops across a given loop will be equal to zero,

**Heating Effect of Currents**

If heat H is produced by a current I flowing in a circuit with resistance R for a time interval of t, H can be mathematically manifested as:

H = I2RT

**Electrical Measuring Instruments**

The main electrical instruments covered in this chapter are:

- Galvanometer to detect the presence of current
- Ammeter to measure the current in a circuit.
- Voltmeter to measure the potential difference in a circuit.
- And, Potentiometer with infinite resistance.

### Chemical Effect of Electric Current and Thermoelectricity

The chemical effect of electric current has wide-ranging applications through the method of electrolysis. It is used in hydrolysis, electroplating, etc.

Seebeck effect explains the phenomenon of thermoelectricity. When there is a temperature gradient in a thermocouple, an electric current is produced which is called thermoelectricity.

### Exercise Discussion for DC Pandey Electricity and Magnetism Solutions Chapter 20: Current Electricity

**Introductory Exercises:**

- In exercise 20.1, basic questions based on the electric current and ohm’s law are asked.
- Exercise 20.2 covers questions based on resistivity and the effect of temperature on an electrical conductor
- In exercise 20.3, questions based on the electromotive force are asked.
- In exercise 20.4, you will learn the application of the current and voltage laws by Kirchhoff in detail using which you will learn to find various elements of a given circuit.
- Exercise 20.5 covers the major electrical instruments and the evaluation of the current and potential difference in given circuits.

**AIEEE Corner (Now a part of JEE): **There are 57 subjective questions and 43 multiple-choice questions in this exercise covering the exam pattern thoroughly. Most questions are based on given electrical circuits and applications of formulae of emf and Kirchhoff’s Laws, etc.

**JEE Corner: **The JEE corner has a broad set of questions, both objective and subjective covering the topics of current electricity such as the heating and chemical effect of current, current, and voltage laws by Kirchhoff, etc. There are match the column, assertion-reasoning problems, and numerical problems based on electrical circuits in this exercise.

## Why Use DC Pandey Electricity and Magnetism Solutions Chapter 20: Current Electricity by Instasolv?

- The answers to the exercise solutions for DC Pandey Electricity and Magnetism Solutions at the Instasolv platform are covered with the same ease, be it a difficult advanced level problem or a beginner problem.
- You will find all your doubts covered using simple methods compatible with your understanding.
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- Refer to DC Pandey Current Electricity Solutions for JEE as well as Class 11 and Class 12 exams.