As conductance is the complement of resistance, there is also a complementary expression of reactance, called susceptance. Mathematically, it is equal to 1/X, the reciprocal of reactance. Like conductance, it used to be measured in the unit of mhos, but now is measured in Siemens. CORRECT OPTION IS 5.

The reciprocal of resistance is given by the unit called the Siemens (S). The reciprocal of a quantity simply means taking the inverse of that quantity. In the case of resistance, the reciprocal is the conductance, which is a measure of how easily current can flow through a material.

Explanation:
Resistance is a fundamental property of a material that determines how strongly it opposes the flow of electric current. It is measured in ohms (Ω). The higher the resistance, the more difficult it is for current to flow.

The reciprocal of resistance is conductance, which is a measure of how easily current can flow through a material. It is the inverse of resistance and is measured in Siemens (S). Conductance is denoted by the symbol G.

The conductance of a material depends on its conductivity, which is a measure of how easily it allows current to flow. Conductivity is the reciprocal of resistivity.

Resistivity is a property of a material that determines how strongly it opposes the flow of electric current. It is measured in ohm-meters (Ω·m). Resistivity is denoted by the symbol ρ.

Conductivity is the reciprocal of resistivity and is given by the formula:
σ = 1/ρ

Where:
σ = conductivity
ρ = resistivity

Conductivity is a measure of how easily a material allows current to flow. Materials with high conductivity are good conductors of electricity, while materials with low conductivity are called insulators.

In summary, the reciprocal of resistance is given by the unit called the Siemens (S). The reciprocal of resistance is conductance, which is a measure of how easily current can flow through a material. Conductance is the inverse of resistance and is measured in Siemens (S). Conductance depends on conductivity, which is the reciprocal of resistivity. Resistivity is a measure of how strongly a material opposes the flow of electric current and is measured in ohm-meters (Ω·m). Conductivity is a measure of how easily a material allows current to flow and is the reciprocal of resistivity.