Question

Find the resistance of wire of
0.65m Radius 0.25
and
resistivity 3x10-6 OHM
​

Answer 1

Complete Question:

Find the resistance of a wire of length 0.65 m, radius 0.25 mm and resistivity 3 * 10^{-6} ohm-metre.

Answer:

Resistance = 9.95 Ohms

Step-by-step explanation:

Given the following data;

Length = 0.65 m

Radius = 0.25 mm to meters = 0.00025 m

Resistivity = 3 * 10^{-6} ohm-metre.

To find the resistance of the wire;

Mathematically, resistance is given by the formula;

`Resistance = P \frac {L}{A}`

Where;

• P is the resistivity of the material.
• L is the length of the material.
• A is the cross-sectional area of the material.

First of all, we would find the cross-sectional area of the wire.

Area of circle = πr²

Substituting into the equation, we have;

Area = 3.142 * (0.00025)²

Area = 3.142 * 6.25 * 10^{-8}

Area = 1.96 * 10^{-7} m²

Now, to find the resistance of the wire;

`Resistance = 3 * 10^(-6) * \frac {0.65}{1.96 * 10^(-7)}`

`Resistance = 3 * 10^(-6) * 3316326.531`

Resistance = 9.95 Ohms