Four electric charges +q, + q, -q and -q are placed at the corners of a square of side 2L (see figure). The electric potential at point A, mid-way between the two charges +q and +q, is
(1)
(2)
(3) Zero
(4)
Three charges, each +q, are placed at the corners of an isosceles triangle ABC of sides BC and AC equal to 2a. D and E are the mid points of BC and CA. The work done in taking a charge Q from D to E is
(1)
(2)
(3)zero
(4)
A series combination of n1 capacitors, each of value C1, is charged by a source of potential difference 4 V. When another parallel combination of n2 capacitors, each of value C2, is charged by a source of potential difference V, it has the same (total) energy stored in it as the first combination has. The value of C2 in terms of C1 is:
1.
2. 16C1
3. 2C1
4.
Three concentric spherical shells have radii a, b and c (a<b<c) and have surface charge densities and respectively. If and denote the potential of the three shells, if c=a+b, we have
(1)
(2)
(3)
(4)
Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be
(1)
(2)
(3)
(4)
The electric potential at a point (x,y,z) is given by
The electric field at that point is
(a)
(b)
(c)
(d)
The mean free path of electrons in a metal is The electric field which can give on an average 2 eV energy to an electron in the metal will be in a unit of :
(1)
(2)
(3)
(4)
Two dielectric slabs of constant K1 and K2 have been filled in between the plates of a capacitor as shown below. What will be the capacitance of the capacitor
(1)
(2)
(3) \(\frac{2\epsilon _{0}A}{d}(\frac{k_{1}+k_{2}}{k_{1}-k_{2}})\)
(4)
What is the equivalent capacitance between A and B in the given figure (all are in farad)
(1)
(2)
(3)
(4)
100 capacitors each having a capacity of 10 μF are connected in parallel and are charged by a potential difference of 100 kV. The energy stored in the capacitors and the cost of charging them, if electrical energy costs 108 paise per kWh, will be?
1. | 107 joule and 300 paise |
2. | 5 × 106 joule and 300 paise |
3. | 5 × 106 joule and 150 paise |
4. | 107 joule and 150 paise |