How does one explain increase in resistivity of a metal with increase in temperature ?
Calculate the current drawn from the battery by the network of resistors shown in the figure.
A point charge Q is placed at point ‘O’ as shown in figure. Is the potential at point A, i.e., , greater, smaller or equal to potential, at point B, when Q is (i) positive, and (ii) negative charge?
For any charge configuration, equipotential surface through a point is normal to the electric field. Justify.
How does the random motion of free electrons in a conductor get affected when a potential difference is applied across its ends ?
An electron is accelerated through a potential difference V. Write the expression for its final speed, if it was initially at rest.
Why is choke coil needed in the use of fluorescent tubes with ac mains ?
Show variation of resistivity of copper as a function of temperature in a graph.