Question

What is ohm in SI unit?

Answer 1

In the International System of Units (SI), the ohm is the unit of electrical resistance. It is denoted by the symbol \( \Omega \).

1 ohm is defined as the resistance between two points of a conductor when a constant potential difference of 1 volt (V) applied across the points produces a current of 1 ampere (A). Mathematically, it is expressed as:

\[ \Omega = \frac{V}{A} \]

where \( V \) is the voltage in volts and \( A \) is the current in amperes.

In essence, an ohm quantifies how strongly a material opposes the flow of electric current.

Answer 2

In the International System of Units (SI), the unit of electrical resistance is the ohm, symbolized by the Greek letter Ω. It measures how strongly a material opposes the flow of electric current.

1. **Definition**: One ohm is defined as the resistance between two points of a conductor when a constant potential difference of one volt (V) applied between these points produces a current of one ampere (A). In mathematical terms:
   
   \[
   1 \, \Omega = \frac{1 \, \text{V}}{1 \, \text{A}}
   \]

2. **Relation to Other SI Units**: The ohm can be expressed in terms of the base SI units:
   
   \[
   1 \, \Omega = 1 \, \text{kg} \cdot \text{m}^2 \cdot \text{s}^{-3} \cdot \text{A}^{-2}
   \]
   
   Where:
   - \(\text{kg}\) is kilograms (unit of mass),
   - \(\text{m}\) is meters (unit of length),
   - \(\text{s}\) is seconds (unit of time),
   - \(\text{A}\) is amperes (unit of electric current).

3. **Practical Example**: If you have a resistor with a resistance of 100 ohms, it means that applying 1 volt of potential difference across this resistor will cause a current of 0.01 amperes (or 10 milliamperes) to flow through it.

The ohm is a fundamental unit in electrical engineering and physics, crucial for analyzing and designing electrical circuits.