A 4μF conductor is charged to 400 volts andthen its plates are joined through a resistance of1 kΩ. The heat produced in the resistance is [1989]
A hollow metal sphere of radius 10 cm is chargedsuch that the potential on its surface is 80 V. Thepotential at the centre of the sphere is [1994]
1 Crore+ students have signed up on EduRev. Have you? Download the App 
The four capacitors, each of 25μ F are connected as shown in fig. The dc voltmeter reads 200 V. The charge on each plate of capacitor is [1994]
If the potential of a capacitor having capacity 6μF is increased from 10 V to 20 V, then increase in its energy will be [1995]
A parallel plate condenser with oil between the plates (dielectric constant of oil K = 2) has a capacitance C. If the oil is removed, then capacitance of the capacitor becomes
What is the effective capacitance between points X and Y?
A capacitor is charged to store an energy U.The charging battery is disconnected. Anidentical capacitor is now connected to the firstcapacitor in parallel. The energy in each of thecapacitor is [2000]
In a parallel plate capacitor, the distance between the plates is d and potential difference across the plates is V. Energy stored per unit volume between the plates of capacitor is
The capacity of a parallel plate condenser is 10μF when the distance between its plates is 8cm. If the distance between the plates is reducedto 4 cm then the capacity of this parallel platecondenser will be [2001]
Energy stored in a capacitor is
A capacitor C_{1} is charged to a potential difference V. The charging battery is then removed and the capacitor is connected to an uncharged capacitor C_{2}. The potential difference across the combination is
A solid spherical conductor is given a charge. The electrostatic potential of the conductor is [2002]
Each corner of a cube of side l has a negative charge, –q. The electrostatic potential energy of a charge q at the centre of the cube is [2002]
Three capacitors each of capacity 4μF are to be connected in such a way that the effective capacitance is 6 μF. This can be done by [2003]
An electric dipole has the magnitude of its chargeas q and its dipole moment is p. It is placed inuniform electric field E. If its dipole moment is along the direction of the field, the force on itand its potential energy are respectively [2004]
A bullet of mass 2 g is having a charge of 2μC.Through what potential difference must it beaccelerated, starting from rest, to acquire a speedof 10 m/s? [2004]
As per the diagram, a point charge +q is placed at the origin O. Work done in taking another point charge –Q from the point A [coordinates (0, a)] to another point B [coordinates (a, 0)] along the straight path AB is:
Two charges q_{1} and q_{2} are placed 30 cm apart, as shown in the figure. A third charge q_{3} is moved along the arc of a circle of radius 40 cm from C to D. The change in the potential energy of the system is where k is
A network of four capacitors of capacity equal to C_{1} = C, C_{2} = 2C, C_{3} = 3C and C_{4} = 4C are conducted to a battery as shown in the figure. The ratio of the charges on C_{2} and C_{4} is: [2005]
A parallel plate air capacitor is charged to apotential difference of V volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates [2006]
Charges +q and –q are placed at points A and B respectively which are a distance 2L apart, C is the midpoint between A and B. The work done in moving a charge +Q along the semicircle CRD is [2007]
Two condensers, one of capacity C and other of capacity C/2 are connected to a Vvolt battery, as shown. [2007]
The work done in charging fully both the condensers is
The electric potential at a point in free space due to a charge Q coulomb is Q × 10^{11} volts. The electric field at that point is [2008]
The energy required to charge a parallel plate condenser of plate separation d and plate area of crosssection A such that the uniform electric field between the plates is E, is [2008]
Three concentric spherical shells have radii a, b and c (a < b < c) and have surface charge densities σ , – σ and σ respectively. If V_{A}, V_{B} and V_{C} denotes the potentials of the three shells, then for c = a + b, we have [2009]
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 [2009]
The electric potential at a point (x, y, z) is given by V = – x2y – xz3 + 4. The electric field at that point is [2009]
A series combination of n1 capacitors, each of value C_{1}, is charged by a source of potential difference 4 V. When another parallel combination of n_{2} capacitors, each of value C_{2}, 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 C_{2} , in terms of C_{1}, is then [2010]
A condenser of capacity C is charged to a potential difference of V_{1}. The plates of the condenser are then connected to an ideal inductor of inductance L. The current through the inductor when the potential difference across the condenser reduces to V_{2} is
Two parallel metal plates having charges + Qand –Q face each other ata certain distance between them. If the plaves are now dipped inkerosene oil tank, the electric field between the plates will
105 videos425 docs114 tests
