The resistance of a piece of wire of length is 20m and cross-sectional area 8×10^-6m^2 is ? [Resistivity of wire =5×10^-7 ohm]
The resistance of a wire is given by the formula:
R = ρL/A
where R is the resistance, ρ is the resistivity, L is the length of the wire, and A is the cross-sectional area.
Substituting the given values, we get:
R = (5×10^-7 ohm) x (20m) / (8×10^-6m^2)
R = 1.25 ohm
Therefore, the resistance of the wire is 1.25 ohm.
To find the resistance of the wire, we can use the formula:
Resistance = (Resistivity * Length) / Area
Given:
Length (l) = 20 m
Cross-sectional area (A) = 8×10^-6 m^2
Resistivity (ρ) = 5×10^-7 ohm
Substituting the values into the formula:
Resistance = (5×10^-7 ohm * 20 m) / (8×10^-6 m^2)
Simplifying:
Resistance = (5/8) * (10^-7/10^-6) * 20
Resistance = (5/8) * 10^-7 * 10^6 * 20
Resistance = (5 * 20) / 8
Resistance = 100 / 8
Resistance = 12.5 ohm
Therefore, the resistance of the wire is 12.5 ohm.