Three capacitors each of 4 are to be connected in such a way that the effective capacitane is 6 . This can be done by connecting them :
1. all in series
2. two in series and one in parallel
3. all in parallel
4. two in parallel and one in series
An electric field N/C exists in a region of space. If the potential at the origin in taken to be zero then potential at x = 2 m, y = 2 m is :
1. -130 V
2. -120 V
3. -140 V
4. -110 V
A uniformly charged solid sphere of radius R has potential V0 (measured with respect to ) on its surface. For this sphere the equipotential surfaces with potentials have radius respectively
Then :
1.
2.
3.
4.
Three concentric metal shells A,B and C of respective radii a,b & c (a<b<c) have surface charge densities respectively. The potential of B is :
1.
2.
3.
4.
Three capacitances, each of 3 , are provided. These cannot be combined to provide the resultant capacitance of :
1. 4.5
2. 1
3. 2
4. 6
The space between the plates of a parallel plate capacitor is filled with a dielectric whose dielectric constant varies with distance as per the relation . The capacitance C of this capacitor would be related to its vacuum capacitance as per relation
1.
2.
3.
4.
If the capacitance of a nanocapacitor is measured in terms of unit 'u' made by combining the electronic charge 'e'. Bohr radius 'a0', Planck's constant 'h' and speed of light 'c' then
1.
2.
3.
4.
In fig it is shown that a system of four capacitors connected across a 10 V battery. Charge that will flow from switch S when it is closed is :
1. 5 from b to a
2. 20 from a to b
3. 5 from a to b
4. zero
Assume that an electric field exists in spacce. Then the potential difference where is potential at the origin and the potential at x = 2 m is :
1. 120 V
2. -120 V
3. -80 V
4. 80 V
A paralle plate capacitor of capacitance 90 pF is connected to a battery of emf 20 V. If a dielectric material of dielectric constant K = 5/3 is inserted between the plates, the magnitude of induced charged will be :
1. 1.2 nC
2. 0.3 nC
3. 2.4 nC
4. 0.9 nC
The equivalent capacitance between A and B in the circuit given below is :
1. 2.4
2. 4.9
3. 3.6
4. 5.4
A parallel plate capacitor with area and separation between the plates 1.5 cm, is connected across a battery of emf V. If the force of attraction between the plates is . The value of V is approximately
1. 250 V
2. 100 V
3. 300 V
4. 150 V
A capacitor is charged up to a voltage V = 60 V by connecting it to battery B through switch (1). Now is disconnected from battery and connected to a circuit consisting of two uncharged capacitors and through switch (2), as shown in figure. The sum of final charges on and is :
1. 40
2. 36
3. 20
4. 54
A charge Q is distributed over two concentric hollow spheres of radii r and R with R>r such that the surface charge densities are equal. The electrical potential at the common center is
1.
2.
3.
4.
A capacitor is charged by using a battery which is then disconnected. A dielectric slab is then introduced between the plates which results in the
1. reduce of charge on the plates and increase of potential difference across the plates
2. increase in the potential difference across the plates and reduction in stored energy, but no change in the charge on the plates
3. decrease in the potential difference across the plates and reduction in the stored energy, but no change in the charge on the plates
4. None of these