Define the conductivity of a conductor. Write its SI unit.

Define temperature coefficient of resistivity.

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.

Define the term mobility of charge carriers in a conductor. Write its S.I. unit.

Give an example of a material each for which temperature coefficient of resistivity is: (i) positive, (ii) negative.

The emf of a cell is always greater than its terminal voltage. Why ? Give reason.

How does the random motion of free electrons in a conductor get affected when a potential difference is applied across its ends ?

Write the expression for the drift velocity of charge carriers in a conductor of length l across which a potential difference V is applied.

How does one explain increase in resistivity of a metal with increase in temperature ?

When electrons drift in a metal from lower to higher potential, does it mean that all the free electrons of the metal are moving in the same direction ?

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 ?

Graph showing the variation of current versus voltage for a material GaAs is shown in the figure, identify the region of :

Draw a graph to show the variation of resistance of a metal wire as a function of its diameter keeping its length and material constant.

Show variation of resistivity of copper as a function of temperature in a graph.