Question

Which of the following factor does not affect the electrical resistance of a wire?

• A. Colour of wire
• B. Length of wire
• C. Diameter of wire
• D. Material of wire

Answer 1

The correct option is A Colour of wire

Resistance is given by:
$R=\frac{\rho L}{A}$
where:
$\rho :$ Resistivity
$L:$ Length
$A:$ Area of cross-section
So, electrical resistance does not depend on the colour of the wire. It depends only on length, cross-section area and material of the wire.
When the length of the wire is increased, the resistance increases. When the diameter of the wire is increased, the resistance decreases. When the material of the wire is changed, the resistivity changes and thus resistance also changes.