Question

Table gives the resistivity of three material in ohm A, B, C
Sample a of resistivityA is 1.6 into 10 to the power minus 8 and resistivity of B is 7.5 into 10 to the power 17and resistivity of C is 44 into 10 to the power minus 6 which one of them is the best conductor and which is an insulator and why? A wire of resistivity P is stretched to twice its length what will be its new resistivity?

Answer 1

Explanation:

(i)The lesser the resistivity of a conductor ,the more it allows electric current to pass through it .

Insulators have the maximum resistivity and conductors have the minimum resistivity.

In the given question the best conductor will be the one having minimum resistivity.

So, material A is the best conductor , since it has minimum resistivity.

AND,

Material B the best insulator since it has maximum resistivity.

(ii)Resistivity of a conductor does not depend on its length .

If the length of the conductor is increased twice ,the resistivity will remain constant.

It will not change.

Hence, after doubling the length of the given wire, resistivity will be P only.

Answer 2

Explanation:

the above answer is correct