Question

What is resistance? Define SI unit of resistance.

Hint:

Resistance depends on the material, length, and cross-sectional area of the conductor. The formula is \( R = \rho \frac{L}{A} \).

Answer 1

Step 1: Defining resistance.
Resistance is the opposition offered by a material to the flow of electric current. It depends on the material, temperature, length, and cross-sectional area of the conductor. The resistance \( R \) is given by the formula: \[ R = \rho \frac{L}{A} \] where \( \rho \) is the resistivity of the material, \( L \) is the length of the conductor, and \( A \) is the cross-sectional area of the conductor.
Step 2: SI unit of resistance.
The SI unit of resistance is the ohm ( \( \Omega \) ). One ohm is defined as the resistance between two points of a conductor when a current of one ampere flows through the conductor with a potential difference of one volt.
Step 3: Conclusion.
Thus, resistance is the opposition to the flow of electric current, and its SI unit is the ohm \( \Omega \).