When the diameter of the conductor is doubled, then its resistance:A) Decreases two timesB) Decreases four timesC) Decreases six timesD) Increases four times

When the diameter of a conductor is doubled, its resistance decreases four times. This is because resistance is inversely proportional to the cross-sectional area of the conductor, and the cross-sectional area of a conductor is directly related to the square of its diameter.

The formula for calculating the resistance of a conductor is:

R = ρ * (L / A)

Where:
R = Resistance
ρ = Resistivity of the material (a constant)
L = Length of the conductor
A = Cross-sectional area of the conductor

When you double the diameter (which effectively means you quadruple the cross-sectional area because the area is proportional to the square of the diameter), the resistance decreases by a factor of 1/4. So, the correct answer is:

B) Decreases four times