Electric potential

Question 1

What is electric potential?

Answer 1

• electric potential at a certain position in any electric field is defined as the work done per unit +ve charge on a +ve test charge when it is moved from infinity to that position
• V

Question 2

What are equipotentials?

Answer 2

• surfaces of constant potential
• test charge moving along an equipotential has constant PE
• no work done by electric field on test charge due to the fiel is at right angles to the equipotentioals

Question 3

What is the potential gradient?

Answer 3

• potential gradient at any position in an electric field is the change of potential per unit charge of distance in a given direction

Question 4

Wgat is the difference between the potential gradient in non-uniform and uniform field?

Answer 4

• non-uniform
  
  • varies according to position and direction
  • the closer the equipotentials, the greater the potential gradient is at right angles to the equipotentials
• uniform
  
  • equally spaced equipotential lines

Question 5

How is the electric field strength linked to potential graident?

Answer 5

• electric field strength is equal to the negative of the potential gradient

Question 6

What is the equation for potential gradient and electric field strength (using potential gradient)

Answer 6

• potential gradient
  
  • ΔV / Δr
• electric field stregth
  
  • -(ΔV / Δr) = E

Question 7

What is the equation for electric potential energy?

Answer 7

kQq / r

=

Question 8

What is the difference between electric potential and electric potential energy

Answer 8

• Electric potential energy is the energy it takes to put a charge in a given place,
  
  • for example, near another charge.
  • If the particle has to be held back (because it is attracted) then the potential energy is negative; that’s because you can get energy from that particle as you move it in. (kQq / r)

Electric potential of a charged particle is the potential energy divided by the electric charge of that particle. (kQq / qr = kQ/ r)