Question

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

P		2.3 × 103 Ω m
Q		2.63 × 10−8 Ω m
R		1.0 × 1015 Ω

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

Answer 1

(a) electric wires: They are made of conductors. Conductors have a low resistivity and so, we will use material Q.

Q	2.63 × 10−8 Ω m: low resistivity

(b) handle for soldering iron: It is made of an insulator. An insulator has a high resistivity and so, we will use material R.

R	1.0 × 1015 Ω: high resistivity

(c) solar cells: They are made of semiconductors. A semiconductor has moderate resistivity and so, we will use material P.

P	2.3 × 103 Ω m: moderate resistivity