Question

The reciprocal of resistance is called
A. Major resistance
B. Conductance
C. Specific resistance
D. None of these

Answer 1

Hint: The resistance offered by a resistor is a measure of the opposition offered by it to the flow of current through it when a potential difference is applied across it. More the resistance, the more is the opposition. Therefore, its inverse will obviously be a measure of how easily current passes through it or how conducting the substance is. Therefore, this measure is called conductance.

Formula used:
$\text{Conductance = }\dfrac{1}{\text{Resistance}}$

Complete step by step answer:
Whenever a potential difference is applied across a conductor, current flows through it. The resistance of the conductor is a measure of the opposition that the conductor offers to this flow of current. Higher the resistance of the body, higher is the opposition to the flow of current. It is measured in Ohm$\left( \Omega \right)$.
The inverse of resistance is conductance. As the name suggests, it is a measure of the ability of the body to conduct electricity or the easy by which current flows through the body. Higher the conductance, lower is the opposition offered by the body to the flow of current. It is measured in Ohm inverse or Mho (Ohm written in reverse, since it is the inverse of resistance) $\left( {{\Omega }^{-1}} \right)$. There is also another unit of conductance known as Siemen $\left( S \right)$.
Hence,
$\text{Conductance = }\dfrac{1}{\text{Resistance}}$

Hence, the correct option is B) Conductance.

Note: Analogous to the relation between resistance and conductance, the same relation exists between specific resistance and specific conductance. Specific conductance of the material of a body is the inverse of the specific conductance of the material of the body. Students should properly understand the differences between resistance and specific resistance, and conductance and specific conductance respectively.