[SOLVED] is the potential energy state function ???

hi,


is potential due to an electric or magnetic or gravitational field a state function......in other words is the work done by an electric field a stat function ??

thnks

eng_boody said:

hi,


is potential due to an electric or magnetic or gravitational field a state function......in other words is the work done by an electric field a stat function ??

thnks

Click to expand...

State functions are characterized by the idea that no matter what path you take to get from point A to point B, the difference between B and A remains the same. An example of how this works can be illustrated using gravitational potential energy. Say you lift a box 5 meters vertically straight up into the air from the surface of the ground (which we shall set to a height of 0 m). You increase its energy by an amount mg h where h = 5m. Now say that you lift a box from the ground level up 1 meter above the ground, walk to the right 5 meters, lift the box 1 more meter, walk to the left 2 meters, raise the box 7 meters, walk to the left 1 more meter, and lower the box 4 meters. How much did the gravitational potential energy change? The same amount as before, mg h where h = 5m, because the box is still only 5 meters above where it started in either case and the potential energy depends only on the final height minus the initial height (it depends only on the final and initial position).

In contrast, you expended a lot more energy (more work) moving the box around than you did just standing in place and lifting it straight up. So the work you did is NOT a state function. This function depends on the path. When you lifted the box straight up you did less work than your body did lugging the box around left and right while lifting it up and down.
So the potential energy is a state function, but the work you did is a path function.

Hope, You got it.

thnks this is helpful