Assertion (A): | Charge on an insolated capacitor does not change by introducing dielectric between the plates of the capacitor. |
Reason (R): | Charge on an isolated system is conserved. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
When a particle with charge \(+q\) is thrown with an initial velocity \(v\) towards another stationary change \(+Q,\) it is repelled back after reaching the nearest distance \(r\) from \(+Q.\) The closest distance that it can reach if it is thrown with an initial velocity \(2v,\) is:
1. | \(\frac{r}{4}\) | 2. | \(\frac{r}{2}\) |
3. | \(\frac{r}{16}\) | 4. | \(\frac{r}{8}\) |
Assertion (A): | A metallic shield in the form of a hollow shell may be built to block an electric field. |
Reason (R): | In a hollow spherical shield, the electric field inside it is zero at every point. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | (A) is false but (R) is true. |
A: | Free electrons move always from a region of higher potential to a region of lower potential. |
B: | The capacitance of the capacitor does not depend upon the nature of the conducting material of the plates of the capacitor. |
1. | only A |
2. | only B |
3. | both A and B |
4. | neither A and B |
Three capacitors each of capacity \(4\) µF are to be connected in such a way that the effective capacitance is \(6\) µF. This can be done by:
1. | connecting all of them in a series. |
2. | connecting them in parallel. |
3. | connecting two in series and one in parallel. |
4. | connecting two in parallel and one in series. |
A capacitor of capacity C1 is charged up to V volt and then connected to an uncharged capacitor C2. Then final P.D. across each will be:
1.
2.
3.
4.
The energy and capacity of a charged parallel plate capacitor are \(E\) and \(C\) respectively. If a dielectric slab of \(E_r=6\) is inserted in it, then the energy and capacity become:
(Assuming the charge on plates remains constant)
1. | \(6 \mathrm E,~6 \mathrm C\) | 2. | \( \mathrm E,~ \mathrm C\) |
3. | \({E \over 6},~6 \mathrm C\) | 4. | \( \mathrm E,~6 \mathrm C\) |
An electric dipole has the magnitude of its charges as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively:
1. | q.E and p.E |
2. | zero and minimum |
3. | q.E and maximum |
4. | 2q.E and minimum |
A bullet of mass 2 g is having a charge of 2 µC. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s?
1. 50 kV
2. 5 V
3. 50 V
4. 5 kV