Classify the following into good conductors, resistors and insulators:
Rubber, Mercury, Nichrome, Polythene, Aluminium, Wood, Manganin, Bakelite, Iron, Paper, Thermocol, Metal coin

(b) What p.d. is needed to send a current of $6 \mathrm{A}$ through an electrical appliance having a resistance of $40 \mathrm{\Omega }$?

An electric circuit consisting of a $0.5 \mathrm{m}$ long nichrome wire $XY,$ an ammeter, a voltmeter, four cells of $1.5 \mathrm{V}$ each and a plug key was set up.
(i) Draw a diagram of this electric circuit to study the relation between the potential difference maintained between the points $\mathit{\text{'}}X\mathit{\text{'}}$ and  $\text{'}Y\text{'}$ and the electric current flowing through $XY.$
(ii) Following graph was plotted between $V$ and $I$ values:

What would be the values of $\frac{V}{I}$ ratios when the potential difference is $0.8 \mathrm{V}, 1.2 \mathrm{V}$ and $1.6 \mathrm{V}$ respectively? What conclusion do you draw from these values?

(iii) What is the resistance of the wire?