Question

The electric potential due to a point charge is given by V = k q / r where q is the charge, r is the distance from q, and k =8.99×109Nm²⁄C^2.

A) Show, in detail, that the SI unit of electric potential is a volt.

B) What are equipotential lines?

C) How are equipotential lines used to obtain the electric field lines?

Answer 1

Solution)

A) We know,

[V] = [kq/r]
= [k][q]/[r]
= (N m²/C²)C/m
= N m / C

Also, we know

N m = J

Work done = Force* displacement

so [W] = J = [Fd] = [F][d] = N m
= J/C
= [Volt]

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B) Equipotential lines lie peependicular to the electeic field.They are like contour lines on map which traces lines of equal altitude or potential.

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C) No work is done along the equipotential surface, Hence, such movement is always perpendicular to the electeic field lines.

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Good luck!:)