# Electrostatic Potential and Capacitance - Online Test

Q1. Work done by a uniform electric field E in moving a charge q a distance d from a to b is
Explaination / Solution:

Force and the work done
Q2. Electric potential energy of two point charges q and  is
Explaination / Solution:

Potential energy of a system of charges is the work done in assembling the charges. Force between two charges q and q0 placed at a distance r apart is Potential energy of the charges is given by
Q3. If a charge moves in an electrical field
Explaination / Solution:

Ambiguous question. Energy may be gained or lost depending on the sign of the charge and the electric field. It can also remain unchanged if the charge moves perpendicular to the direction of the field.

Q4. Electric Potential V at a point in an electrical field is
Explaination / Solution:

Electric potential V is the work done in bringing unit positive charge from infinity to the point in an electric field, and the potential energy  is the work done in bringing any finite charge from infinity to the point in an electric field. They are related as, .If q =1C,
Q5. In circuits, a difference in potential from one point to another is often called
Explaination / Solution:

Voltage is the common term used for potential difference or e m f.

Q6. If a positive charge moves in the direction of the electric field
Explaination / Solution:

A positive charge experiences a force in the direction of the field. If it moves in the direction of the field, positive work is done by the electric field on the charge. Potential energy of the charge increases only when an external source does work on the charge against the direction of the field- eg: when the charge is moved against the direction of the field

Q7. If a positive charge moves opposite to the direction of the electric field
Explaination / Solution:

A positive charge experiences a force in the direction of the field. If it moves opposite to the direction of the field, negative work is done by the electric field on the charge. Potential energy of the charge increases since an external source is required to do work on the charge against the direction of the field, and the work done is stored in the charge as its potential energy.

Q8. Electric Potential is
Explaination / Solution:

Electric potential V is the work done in bringing unit positive charge from infinity to the point in an electric field, and the potential energy  is the work done in bringing any finite charge from infinity to the point in an electric field. They are related as,

Q9. The unit of potential difference as used in electrical circuits is
Explaination / Solution:

Volt is the unit of potential difference.

Q10. Electric potential at a distance r from a point charges q is
Explaination / Solution:

Electric potential at a point V is the work done in bringing unit positive charge from infinity to the point in an electric field.