Question

8. Electricalresistivities of some substances at 200c are given below.

Silver – 1.60 x 10-8 ohm metre Copper – 1.62 x 10-8 ohm metre Mercury -94.0 x 10-8 ohm metre

Tungsten – 5.20 x 10-8 ohm metre Nichrome – 100 x 10-6 ohm metre

Answer the following questions in relation to them.

i)Among silver and copper , silver is a better conductor why?

ii) Which material would you advise to be used in electrical heating devices?​

Answer 1

Answer:

i) Silver is the better conductor because it has more free electrons in it than copper. It is also because copper has a resistivity of 1.7 X 10-8 ohms, whereas silver has a lower resistivity at 1.6 X 10-8 ohms.

ii) Nichrome is because the resistivity of an alloy is more than that of a metal and alloy does not burn (or oxidise) even at higher temperature. Out of the given substances, nichrome is an alloy, so nichrome is used in electrical heating devices.