Nichrome and copper wires of same length and same radius are connected in series. Current I is passed through them. Which wire gets heated up more ? Justify your answer.

Plot a graph showing the variation of current I versus resistance R, connected to a cell of emf E and internal resistance r.

Two dipoles, made from charges ± q and ± Q respectively, have equal dipole moments. Give the (i) ratio between the ‘separations’ of these two pairs of charges, (ii) angle between the dipole axes of these two dipoles.

Two equal balls having equal positive charge ‘q’ coulombs are suspended by two insulating strings of equal length. What would be the effect on the force when a plastic sheet is inserted between the two ?

Two point charges ‘q1’ and ‘q2’ are placed at a distance ‘d’ apart as shown in the figure. The electric field intensity is zero at a point ‘P’ on the line joining them as shown. Write two conclusions that you can draw from this.

What is the value of the angle between the vectors $\stackrel{\rightarrow}{p}$and $\stackrel{\rightarrow}{E}$ for which the potential energy of an electric dipole of dipole moment $\stackrel{\rightarrow}{p}$, kept in an external electric field $\stackrel{\rightarrow}{E}$, has the maximum value.

Why should electrostatic field be zero inside a conductor ?

A point charge +Q is placed in the vicinity of a conducting surface. Draw the electric field lines between the surface and the charge.

Figure shows a point charge + Q, located at a distance R/2 from the centre of a spherical metal shell. Draw the electric field lines for the given system.

In the given figure, charge +Q is placed at the centre of a dotted circle. Work done in taking another charge +q from A to B is W₁ and from B to C is W₂. Which one of the following is correct ? i) W₁ > W₂ (ii) W₁ = W₂ (iii) W₁ < W₂

What is the amount of work done in moving a point charge around a circular arc of radius r at the center where another point charge is located ?

Why do the electric field lines never cross each other ?

Why do the electrostatic field lines not form closed loops ?

A charge ‘q’ is moved from a point A above a dipole of dipole moment ‘p’ to a point B below the dipole in equatorial plane without acceleration. Find the work done in the process.

A device ‘X’ is connected to an ac source V = V₀ sin(ωt). The variation of voltage, current and power in one complete cycle is shown in the following figure. (i) Which curve shows power consumption over a full cycle? (ii) Identify the device ‘X’.