A point charge +Q is placed at point O as shown in the figure. Is the potential difference – positive, negative or zero ?
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.
Figure shows the field lines due to a positive charge. Is the work done by the field in moving a small positive charge from Q to P, positive or negative? Give reason.
Obtain the expression for the potential due to an electric dipole of dipole moment p at a point ‘d’ on the axial line.
Draw a plot showing the variation of (i) electric field (E) and (ii) electric potential (V) with distance r due to a point charge Q.
Derive an expression for potential due to a dipole for distances large compared to the size of the dipole. How is the potential due to dipole different from that due to single charge ?
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.
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 are electric field lines perpendicular at a point on an equipotential surface of a conductor ?
Give an example of a material each for which temperature coefficient of resistivity is:
(i) positive, (ii) negative.
Why is choke coil needed in the use of fluorescent tubes with ac mains ?
Two identical cells, each of emf E, having negligible internal resistance, are connected in parallel with each other across an external resistance R. What is the current through this resistance ?
An electron is accelerated through a potential difference V. Write the expression for its final speed, if it was initially at rest.
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.