Potential Energy of Two Point Charges

Q.

……… of a two-particle system depends only on the separation between them.

Q. When separation between two charges is increased, the electric potential energy

1. Increases
2. Decreases
3. Remains the same
4. May increase or may decrease

Q.

A charge of +10 C is fixed at the origin. Choosing the reference point at A(1, 2), the change in potential energy of the system when a charge of +1C is taken from A to infinity is?

1. Positive
2. Negative
3. Zero
4. None of these

Q. Potential energy is only defined for a system of particles.

1. False
2. True

Q. A charged particle $q$ is shot from a large distance towards another charged particle $Q$ which is fixed, with a speed $v$. It approaches $Q$ up to a closest distance $r$ and then returns. If $q$ was given a speed $2v$, the distance of closest approach would be

1. $2r$
2. $r$
3. $\frac{r}{2}$
4. $\frac{r}{4}$

Q.

There are two point charges of +1C each separated by 10m in vacuum. Calculate the change in potential energy of the system if they are brought to a separation of 5m.

1. $9\times {10}^{9}J$

2. $9\times {10}^{8}J$

3. $9\times {10}^{7}J$

4. None

Q.

Assuming potential energy at infinite separation is zero, what is the Potential Energy of a two charge system if the charges are both +10C and are separated by 10m?

1. $9\times {10}^{9}J$

2. $9\times {10}^{10}J$

3. $9\times {10}^{11}J$

4. None of these