# A charge of #7 C# is at the origin. How much energy would be applied to or released from a # 5 C# charge if it is moved from # (-3 , 7 ) # to #(-7 ,-2 ) #?

##### 1 Answer

#### Explanation:

I'll work out the electric potential at points P and Q.

Then I will use this to work out the potential difference between the 2 points.

This is the work done by moving a unit charge between the 2 points.

The work done in moving a 5C charge between P and Q can therefore be found by multiplying the potential difference by 5.

We need to find the length of PR and PQ which can be done using Pythagoras:

and:

The electric potential due to a charge

So the potential at point

The potential at

So the potential difference is given by:

So the work done in moving a 5C charge between these 2 points is given by:

This is the work done on the charge.

There are no units of distance given. If this was in meters then