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The electric potential on the axis of an electric dipole at a distance ‘r from it’s centre is V. Then the potential at a point at the same distance on its equatorial line will be ______.
Concept: Potential Due to a Point Charge
Draw equipotential surfaces for (i) an electric dipole and (ii) two identical positive charges placed near each other.
Concept: Equipotential Surfaces
A point P lies at a distance x from the midpoint of an electric dipole on its axis. The electric potential at point P is proportional to ______.
Concept: Potential Due to an Electric Dipole
A parallel plate capacitor (A) of capacitance C is charged by a battery to voltage V. The battery is disconnected and an uncharged capacitor (B) of capacitance 2C is connected across A. Find the ratio of final charges on A and B.
Concept: Capacitors and Capacitance
A parallel plate capacitor (A) of capacitance C is charged by a battery to voltage V. The battery is disconnected and an uncharged capacitor (B) of capacitance 2C is connected across A. Find the ratio of total electrostatic energy stored in A and B finally and that stored in A initially.
Concept: Energy Stored in a Charged Capacitor
A point charge q0 is moving along a circular path of radius a, with a point charge Q at the centre of the circle. The kinetic energy of q0 is ______.
Concept: Electrical Potential Energy of a System of Two Point Charges and of Electric Dipole in an Electrostatic Field
Depict the orientation of an electric dipole in (a) stable and (b) unstable equilibrium in an external uniform electric field. Write the potential energy of the dipole in each case.
Concept: Potential Energy in an External Field >> Potential Energy of a Dipole in an External Field
Three-point charges Q, q and -q are kept at the vertices of an equilateral triangle of side L as shown in the figure. What is
- the electrostatic potential energy of the arrangement? and
- the potential at point D?
Concept: Electrical Potential Energy of a System of Two Point Charges and of Electric Dipole in an Electrostatic Field
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. What is the work done in moving a charge +Q along the semicircle CRD?
Concept: Potential Energy of a System of Charges
A dielectric slab of thickness 't’ is kept between the plates of a parallel plate capacitor with plate separation 'd' (t < d). Derive the expression for the capacitance of the capacitor.
Concept: Capacitance of a Parallel Plate Capacitor with and Without Dielectric Medium Between the Plates
A capacitor of capacity C1 is charged to the potential of V0. On disconnecting with the battery, it is connected with an uncharged capacitor of capacity C2 as shown in the adjoining figure. Find the ratio of energies before and after the connection of switch S.
Concept: Combination of Capacitors
Obtain the equivalent capacitance of the network shown in the figure. For a 300 V supply, determine the charge on each capacitor.
Concept: Capacitors and Capacitance
The plot of the variation of potential difference across a combination of three identical cells in series, versus current is shown below. What is the emf and internal resistance of each cell ?
Concept: Cells, Emf, Internal Resistance
A battery of emf 12 V and internal resistance 2 Ω is connected to a 4 Ω resistor as shown in the figure.
(a) Show that a voltmeter when placed across the cell and across the resistor, in turn, gives the same reading.
(b) To record the voltage and the current in the circuit, why is voltmeter placed in parallel and ammeter in series in the circuit?
Concept: Cells, Emf, Internal Resistance
What is its relation with relaxation time?
Concept: Drift of Electrons and the Origin of Resistivity
When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 x 10-4 m/s. If the electron density in the wire is 8 x 1028 m-3, calculate the resistivity of the material of the wire.
Concept: Potential Difference and Emf of a Cell
Two identical cells of emf 1.5 V each joined in parallel, supply energy to an external circuit consisting of two resistances of 7 Ω each joined in parallel. A very high resistance voltmeter reads the terminal voltage of cells to be 1.4 V. Calculate the internal resistance of each cell.
Concept: Cells, Emf, Internal Resistance
Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 2.5 × 10−7 m2 carrying a current of 1.8 A. Assume the density of conduction electrons to be 9 × 1028 m−3.
Concept: Drift of Electrons and the Origin of Resistivity
Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0 × 10−7 m2 carrying a current of 1.5 A. Assume the density of conduction electrons to be 9 × 1028 m−3
Concept: Drift of Electrons and the Origin of Resistivity
Estimate the average drift speed of conduction electrons in a copper wire of cross-sectional area 2·5 × 10−7 m2 carrying a current of 2·7 A. Assume the density of conduction electrons to be 9 × 1028 m−3
Concept: Drift of Electrons and the Origin of Resistivity
