Question

The electrical resistivities of three materials A, B and C are given below:
A 1 x 10 -8 Ω m
B 1 x 10 15 Ω m
C 100 x 10 -6 Ω m
Which material will be used for making the following: (Justify your answers)
i. covering of connecting wires for insulation?
ii. a heating element of an electric geyser?

Answer 1

Answer:

2 a heating element of an electric geyser.

Answer 2

Answer:

i) B should be perfect.

ii) A should be perfect.

Explanation:

i) the more resistivity way the more insulation.

ii) the less resistivity the way more heat, as heat is equal to:

$\frac{v {}^{2} }{r}$

also 1 x 10 ^-8 ohm meter is of alloys which has a high melting point.