Question

if length of wire is increased 4 times of its original length then how will resistance and resistivity affected

Answer 1

New resistance = n^2R
= 16R
so new resistance becomes 16 times the original one.

Resistivity = p = R A/l
new resistivity = R A/4l
so new resistivity is 1/4 of previous one

Answer 2

Resistance will increase 4 times and resistivity will remain constant.

Resistance:

The property by which conductors tend to oppose the flow of electrons is termed as resistance. It is represented by ohm(Ω)

Resistivity:

The strength by which a conductor repels the flow of electrons is termed as resistivity.  It is represented by rho(ρ).

Dependence of resistance:

• Length: The resistance of an object is directly proportional to the length of the object.
• Area of cross-section- The resistance of an object is inversely proportional to the area of cross-section of the object.

Dependence of resistivity:

• Resistivity is a characteristic property. It does not vary with increase or decrease in dimensions.

Hence, when the length of wire is increased, only resistance increases.