## Electrostatic Potential and Capacitance

CBSE Class 12 - Physics
(Short Q and A)

Q1: Define Electrostatic Potential.

Answer: The electrostatic potential at a point is defined as amount of work done per unit positive test charge in moving the test charge from infinity to that point against the electrostatic force due to the electric field.
Q4: Is electric potential a scalar quantity or vector quantity?

Q2: Name the physical quantity whose SI unit is Joule coulomb⁻ⁱ?

Q3: Does the electric potential increase or decrease along the electric line of force?

Answer: It decreases along the electric line of force.

Q4: Is electric potential a scalar quantity or vector quantity?

Q5: Define electric potential difference.

Answer: It is the amount of work done per unit positive test charge in bringing a small positive charge from a point of lower potential to the point of higher potential along any path.

Q6: What is the work done in moving a charge over an equipotential surface?

Q7: Is there any conductor which can be given almost unlimited charge?

Q8: What is the difference between electric potential and potential energy? State the relation between the two.

Answer: Electric potential is the work done per unit charge. While potential energy is the total work done in bringing different charges from infinity to their respective positions.

electric potential energy
Electric potential = ─────────────────────────
charge

Q9: When we rub a balloon it becomes negatively charge and it has several thousands say 50000 volt. Still it does give shock to us, Why?

Answer: Because its electric potential energy is very low. There flows very little energy transfer when the balloon discharges.

Q10: Define equipotential surface.

Answer: The surface at a point of which the electric potential is same is called equipotential surface.

Q11: What kind of charging occurs during thunderstorms?

Answer: Both inductive and non-inductive (interface) charging.

Q12: Differentiate between polar and non-polar dielectrics.

Answer: A dielectric whose molecules possess electric dipole moment even when electric field is not applied is called polar dielectric.

A dielectric whose molecules do not possess permanent dipole moment is called non-polar dielectric.

Q13: What is meant by the term 'electrically polarized'?

Answer: The term applies to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge, that atom or molecule is said to be electrically polarized.

Q14: What is a capacitor?

Answer: Capacitor is an arrangement of increasing the capacity of a conductor so as to store a large quantity of charge.

Q15: Name the physical quantity whose SI unit is coulomb/volt.  