Electric Potential Class 12 Physics Numerical with Answers

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Last Updated on August 2, 2024 by XAM CONTENT

Hello students, here you will find numerical on electric potential with answers. Before we start solving the numerical, let’s see some important points and formulae. This will help you to solve the problems efficiently.

Understanding Electric Potential

Electric potential is a fundamental concept in physics that helps us understand how electric charges interact in an electric field. Think of it as the “electric pressure” that pushes charges around, much like how water pressure pushes water through pipes.

Imagine you have a hill, and you place a ball at the top. The higher the hill, the more potential energy the ball has because gravity will cause it to roll down. Similarly, in an electric field, electric potential is the energy per unit charge that a charge would have due to its position.

To break it down further, let’s use an analogy. Consider a water slide at a theme park. The higher you go up the slide, the more potential energy you have because you’ll go faster and farther when you slide down. In the same way, if you place a positive charge near another positive charge, it will have high electric potential energy because like charges repel each other, and you would need to do work to bring them close together.

Electric Potential due to Point Charge

Consider a positive point charge q placed at the origin O. We wish to calculate its electric potential at a point P at distance r from it, as shown in Fig.

By definition, the electric potential at point P will be equal to the amount of work done in bringing a unit positive charge from infinity to the point P.

Suppose a test charge q₀ is placed at point A at distance x from O. By Coulomb’s law, the electrostatic force acting on charge q₀ is

The total work done in moving the charge q₀ from infinity to the point P will be

Hence the work done in moving a unit test charge from infinity to the point P, or the electric potential at point P is

A higher electric potential means that more work is required to bring a unit positive charge from infinity to that point. It also indicates a stronger electric field around that point, causing charges to experience greater force.

In the below section, we are providing numerical problems based on Electric Potential for Class 12 Physics.

Electric Potential Class 12 Physics Numerical with Answers

Formula used:

1. Potential difference

2. Electric potential due to a point charge q at distance r from it,

3. Electric potential at a point due to N point charges,

4. Electric potential at a point due to a dipole,

Units used:

Charge q is in coulomb, distance r in metre, work done W in joule and potential difference V in volt.

Question 1: If 100 J of work has to be done in moving an electric charge of 4C from a place, where potential is -10 V to another place, where potential is V volt, find the value of V.

Ans. 15 V

Question 2: (i) Calculate the potential at a point P due to a charge of 4 × 10^-7 C located 9 cm away, (ii) Hence obtain the work done in bringing a charge of 2 × 10^-9 C from infinity to the point P. Does the answer depend on the path along which the charge is brought?

Ans. (i) 4 × 10⁴ V (ii) 8 × 10^-5 J
No, the answer does not depend on the path along which the charge is brought.

Question 3: A metal wire is bent in a circle of radius 10 cm It is given a charge of 200 μC which spreads on it uniformly. Calculate the electric potential at its centre.

Ans. 18 x 10⁶ V

Question 4: Two charges 3 × 10^-8 C and – 2 × 10^-8 C are located 15 an apart. At what point on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.

Ans. 9 cm and 45 cm away from the positive charge on the side of the negative charge.

Question 5: Two charges -q and +q are located at points A (0, 0, -a) and B (0, 0, +a) respectively. How much work is done in moving a test charge from point P (7, 0, 0) to Q (-3, 0, 0)?

Ans. zero
Explanation: Points P and Q are located on the equatorial line of the electric dipole and potential of the dipole at any equatorial point is zero.

Question 6: The work done in moving a charge of 3 C between two points is 6J. What is the potential difference between the two points?

Ans. 2 V

We hope the given numerical on Electric Potential for Class 12 Physics helps you in your learning.

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