A piece of wire of resistance 20 Ω is drawn out so that its length is increased to twice its original length. Calculate the resistance of the wire in the new situation.

The resistivity of copper metal depends on only one of the following factors. This factor is :

If the area of cross-section of a resistance wire is halved, then its resistance becomes :

The electrical resistivities of three materials P, Q and R are given below :

P 2.3 x 10³ Ω m

Q 2.63 x 10^-8 Ω m

R 1.0 x 10¹⁵ Ω m

Which material will you use making (a) electric wires (b) handle for soldering iron, and (c) solar cells? Give reasons for your choices.

The electrical resisitivities of four materials A, B, C and D are given below :

A) 110 x 10^-8 Ω m

B) 1.10 x 10¹⁰ Ω m

C) 01.0 x 10^-8 Ω m

D) 2.3 x 10³ Ω m

Which material is : (a) good conductor (b) resistor (c) insulator, and (d) semi-conductor ?