Question

2. A mobile -4C charge, initially at rest, is located 3.5m away from a fixed, stationary charge of value+250C. Determine the change in potential energy when the mobile charge is brought to a location 1.2maway from the fixed charge.

Answer 1

Given:

The charge is q1 = -4C

The charge is q2 = 250 C

The initial distance is r1 = 3.5 m

The final distance is r2 = 1.2 m

To find the change in potential energy.

Step-by-step explanation:

The change in potential energy can be calculated by the formula

`\begin{gathered} \Delta U=(kq1q2)/(r2)-(kq1q2)/(r1) \\ =kq1q2((1)/(r2)-(1)/(r1)) \end{gathered}`

Here, the constant is

`k=\text{ 9}*10^9\text{ N m}^2\text{ /C}^2`

On substituting the values, the change in potential energy will be

`\begin{gathered} \Delta U=9*10^9*4*250((1)/(1.2)-(1)/(3.5)) \\ =4.92*10^(12)\text{ J} \end{gathered}`