# Physics Class 12 NCERT Solutions: Chapter 2 Electrostatic Potential and Capacitance Part 5 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q: 12. A charge of is located at the origin. Calculate the work done in taking a small charge of from a point to a point , via a point .

Charge located at the origin,

Magnitude of a small charge, which is taken from a point P to point R to point

All the points are represented in the given figure.

Point P is at a distance, , from the origin along z-axis.

Point Q is at a distance, , from the origin along y-axis

Potential at point P,

Potential at point P,

Work done (W) by the electrostatic force is independent of the path.

Where,

Therefore, work done during the process is .

Q: 13. A cube of side has a charge at each of its vertices. Determine the potential and electric field due to this charge array at the centre of the cube.

Length of the side of a cube

Charge at each of its vertices

A cube of side b is shown in the following figure.