Question

(i) A substance has nearly zero resistance at a temperature of $1K$. What is such a substance called?

(ii) State any two factors which affect the resistance of a metallic wire.

Answer 1

1. When a substance has nearly zero resistance at a temperature of $1K$, the substance is called a superconductor.
2. Resistance of a metallic wire is given by $R=\frac{\rho L}{A}$. Where, $R=Resis\tan ceofwire,L=Lengthofwire,A=Crosssectionalarea,and\rho =Resistivityofwire.$
3. So, the resistance of a metallic wire depends on the length of the wire.
4. The resistance of a metallic wire depends on the cross-sectional area of the metallic wire.