Question

The unit of resistance is:
(a) Mho
(b) Ohm
(c) Farad
(d) Ampere

Answer 1

Hint: Resistance has only one SI unit which is ohm. As the resistance is just an opposite force towards current, ohm as being its unit is also used to measure the value of opposition to electric current in any circuit.

Complete step-by-step solution:
First, we are going to discuss the resistance.
Resistance: If in any circuit, there is any level of opposition towards the current flow then we say that there is a resistance present in a circuit. It is simply an opposition towards electric flow in any circuit.
We always measure resistance in ohm. Ohm is denoted by $\Omega $. Ohm is a SI unit of resistance basically. It looks like a simple unit but it has many definitions. If a current is given to us and the current is measured in Ampere, the resistance is measured in Volts per unit Ampere then it is called ohm. Similarly, if we are given Watts and we are calculating it by Ampere so, ohm will be $\dfrac{W}{{{A}^{2}}}$.
Additional information:
There are many denotations that are given to ohm. The representation of ohm can be as follows:
$\text{ }\!\!\Omega\!\!\text{ =}\dfrac{\text{Volts}}{\text{Watt}}\text{,}\dfrac{\text{Second}}{\text{Farad}}\text{,}\dfrac{\text{Joule}}{\text{sec}\text{.Coloumb}}$.
We must have seen such types during calculations.
Not only these, but we have also been provided with other information than this. There are some useful conversions of ohm is given as $1m\Omega ={{10}^{-3}}\Omega $ where $m\Omega $ is called mili-ohm, $1k\Omega ={{10}^{3}}\Omega $ where $k\Omega $ is called kilo-ohm. Also, $1M\Omega ={{10}^{6}}\Omega $ where $M\Omega $ is known as mega-ohm.
Hence the correct option is (b).

Note: Ohm is used in many calculations which give us the sense of the level of resistance present in a circuit. If we have knowledge about the SI units given in the question then also we will be able to answer it. The SI unit mho basically represents electrical conductivity, farad always represents electrical capacitance and Ampere is used in describing the value of electric current present in any type of circuit. Not only this, if a volt was given in the options then, but we will also know that it is used for calculating electric potential in a circuit.