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Very Short Question and Answers - Electric Potential and Potential Difference

Q 1.
What is electric potential at a point in an electric field?

Ans:

Electric potential at a point is the amount of work done in bringing a unit positive charge from infinity to that point, without any acceleration.

Q 2.
What is the SI unit of electric potential?

Ans:

The SI unit of electric potential is Volt (V).

Q 3.
Write the formula for electric potential in terms of work and charge.

Ans:

Electric Potential (V) = Work done (W) / Charge (q), or V = W/q.

Q 4.
If 10 Joules of work is done to move 2 Coulombs of charge, what is the electric potential at that point?

Ans:

V = W/q = 10 J / 2 C = 5 V.

Q 5.
Define potential difference.

Ans:

Potential difference between two points is the work done in moving a unit charge from one point to another against the electric field.

Q 6.
Which instrument is used to measure potential difference?

Ans:

A voltmeter is used to measure potential difference.

Q 7.
How should a voltmeter be connected in a circuit?

Ans:

A voltmeter should be connected in parallel to the component whose potential difference is to be measured.

Q 8.
What does a reading of 1.5 V across a battery mean in terms of work and charge?

Ans:

It means 1 Joule of work is done for every 1 Coulomb of charge moved by the battery (for a 1.5V battery, 1 C gains 1.5 J of energy).

Q 9.
What drives electric current through a circuit?

Ans:

Potential difference (voltage) between two points drives electric current through a circuit.

Q 10.
Explain the water tank analogy for electric potential.

Ans:

Electric potential is like water pressure in a tank: higher pressure at the top (high potential), lower at the bottom (low potential), causing water (charge) to flow.

Q 11.
If the work done to transfer 3 C of charge is 21 J, what is the potential difference?

Ans:

Potential difference (V) = Work done (W) / Charge (q) = 21 J / 3 C = 7 V.

Q 12.
State the relationship between potential difference and work done.

Ans:

Potential difference equals the work done per unit charge to move the charge between two points (V = W/q).

Q 13.
How is electric potential similar to gravitational potential energy?

Ans:

Just as moving a mass against gravity increases its potential energy, moving a charge against an electric field increases its electric potential.

Q 14.
What is the potential difference provided by household electricity in India?

Ans:

The potential difference in Indian households is 220 V.

Q 15.
Give one example where potential difference is used in daily life.

Ans:

Batteries in devices like torch lights provide a potential difference to drive current.

Q 16.
What happens to electric current if there is no potential difference across a wire?

Ans:

If there is no potential difference, no electric current will flow through the wire.

Q 17.
Why is the potential at infinity considered zero?

Ans:

By convention, the potential at infinity is taken as zero to provide a

reference
point for measuring electric potential.

Q 18.
How much work is needed to move a 5 C charge through a potential difference of 12 V?

Ans:

Work done (W) = Potential difference (V) × Charge (q) = 12 V × 5 C = 60 J.

Q 19.
Why do we prefer to measure potential difference rather than absolute potential?

Ans:

Because current flows due to the difference in potential between two points, and most practical effects in circuits depend on this difference, not on absolute potential values.

Q 20.
A voltmeter is connected across a bulb and shows 6 V. What does this tell us?

Ans:

This means that for every 1 Coulomb of charge passing through the bulb, 6 Joules of energy are converted (into heat and light) in the bulb.

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