Sunday 5 June 2011

Gravitational Potential vs. Electric Potential

Gravitational Potential vs. Electric Potential

Any matter lifted from the surface of the earth has a potential energy. Thisis given by the formula PE=mgh, and the potential energy can be altered by changing its height. The  also can be changed by changing distance between two charges.



  Check!
Earth and baseball Gravitational potential energy equals to product of the mass of an object, gravitational field force, and its height from the earth.PEG = mgh
where:
  • m is the mass of the ball (kg),
  • g is the gravitational field force (g = 9.8 m/s2), and
  • h is the distance between the ball and the earth (m).



 
Electric potential energy equals to the electric potential energy divided by charge. PE = qEd (see right)
where:
  • q is the charge of an object (C),
  • E is electric field produced by Q (N/C), and
  • d is the distance between the two charges. (see right)





Electric potential energy


 
Electric potential is called voltage, which can be derived from above equation.
Electric potential and voltage
Voltage is also related to force.
V = Ed = (F/q)*d = Fd/q= W/q
(W = Fd -- force times displacement in the direction of force is work (J))
A high voltage means that each individual charge is experiencing a large force. A low voltage means that each individual charge is experiencing a small force.
 

  electric charge of A electric charge of B
  "q" on A has smaller force than "q" on B. If the distance of B is one half of that of A, the force acting on B is twice as large as A because the force is inversely proportional to the square of the distance between two charges.

No comments:

Post a Comment