Two cells of emfs 1.5 V and 2.0 V having internal resistances 0.2Ω and 0.3Ω respectively are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.
Two cells of emfs E₁ & E₂ and internal resistances r₁ & r₂ respectively are connected in parallel. Obtain expressions for the equivalent.
(i) resistance and
(ii) emf of the combination
Two electric bulbs P and Q have their resistances in the ratio of 1 : 2. They are connected in series across a battery. Find the ratio of the power dissipation in these bulbs.
Two cells of emf and have internal resistance and . Deduce an expression for equivalent emf of their parallel combination.
Plot a graph showing the variation of current I versus resistance R, connected to a cell of emf E and internal resistance r.
Calculate the current drawn from the battery by the network of resistors shown in the figure.
In the circuit shown in the figure, find the total resistance of the circuit and the current in the arm CD.
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.
Three concentric metallic shells A, B and C of radii a, b and c (a < b < c) have surface charge densities +σ, –σ and +σ respectively as shown in the figure.
Draw a plot showing the variation of resistivity of a (i) conductor and (ii) semiconductor, with the increase in temperature. How does one explain this behaviour in terms of number density of charge carriers and the relaxation time ?
An electric dipole is placed in a uniform electric field with its dipole moment parallel to the field. Find
(i) the work done in turning the dipole till its dipole moment points in the direction opposite to .
(ii) the orientation of the dipole for which the torque acting on it becomes maximum.
A battery of emf 10 V and internal resistance 3 ohm is connected to a resistor. If the current in the circuit is 0.5 A, find :
(i) the resistance of the resistor;
(ii) the terminal voltage of the battery.
Two point charges q and –2q are kept d distance apart. Find the location of the point relative to charge q at which potential due to this system of charges is zero.
Two charges q and –3q are placed on x-axis separated by distance d. Where a third charge 2q should be placed such that it will not experience any force ?