Why electric potential near an isolated proton is positive (3/5)
- Electric potential is defined as zero at infinity.
- A unit positive test charge experiences a repulsive force from the proton
- Work is done by an external force against this repulsive force to move the charge from infinity towards the proton
Why electric potential near an isolated electron is negative
- Electric potential is defined as zero at infinity
- A unit positive test charge experiences an attractive force from the electron
- Work is done by the attractive force as the charge moves from infinity towards the electron.
Definition of electric field (1/2)
- Force per unit positive charge
Definition of electric potential at a point (2/3)
- Work done per unit charge
- in moving a positive test charge from infinity to the point
Coulomb's Law (2/3)
- The electric force between two point charges is directly proportional to the product of the charges
- and is inversely proportional to the square of their separation
Why is electric field inside a conducting hollow sphere zero (1/3)
- A charged particle placed inside experiences equal forces in all directions, so the resultant force and field is zero.
Relationship between electric field and electric potential
Why cant total electric potential and resultant electric field be simultaneously zero at point P
- For total electric potential to be zero, X and Y must be oppositely charged.
- For resultant electric field to be zero, the fields due X and Y at P must be in opposite directions, which requires the charges to have the same sign.
- The signs of the charges cannot simultaneously be both the same and opposite
