Electrostats 1

Electricity and Magnetism Level 3

Two Positively charged particles $X$ and $Y$ are initially far away from each other and at rest. $X$ begins to move towards $Y$ with some initial velocity. The total momentum and energy are $p$ and $E$ $\text{\_\_\_\_\_\_\_\_\_\_\_\_\_}$ .

if Y is fixed,E is conserved,but not p if both are free,E is conserved,but not p if both are free to move p is conserved and not E if Y is fixed,both p and E is conserved

1 solution

Rishi Sharma
Jun 10, 2016

Option(A): If Both X and Y are free to move there will be no external force acting on the system. Hence p is conserved. Also electrostatic force is conservative in nature. Hence E will also be conserved. So option A is wrong.

Option(B): Same reasoning shall apply Hence Option B is also wrong.

Option(C): If we fix Y. we have to apply some external force. Hence there will be some external force on the system so p is not conserved. Again this force will not do any work hence only electrostatic will change affect the energy of system hence E is conserved. So option C is $\boxed{correct}$

Option(D): Same reasoning shall apply and hence D is wrong