Question

Resistance of a conductor does not depend upon.
A. length of the conductor
B. Thickness of the conductor
C. temperature of the conductor
D. humidity of the conductor

Answer 1

Hint: Resistance is the ability of a conductor to resist or oppose the flow of charges through it when a potential difference is created across the conductor. It depends on the material of which it is made. It also depends on the shape and size of the conductor.

Complete step by step answer:
Resistance is the ability of a conductor of given length (l) and cross sectional area (A), to resist or oppose the flow of charges through it when a potential difference is created across the conductor.
The resistance of the given conductor depends on the length of the conductor and also the cross sectional area of the conductor.
Resistance of a conductor is directly proportional to its length and inversely proportional to its cross sectional area.
This means that if two cylindrical conductors of equal cross sectional area but one is longer than the other conductor in length. The resistance of the longer conductor will be more than the shorter one.
If two cylindrical conductors of equal lengths but one has greater cross sectional area than the other conductor does, then the resistance of the conductor with smaller cross sectional area will be more than the one, which has greater cross sectional area.
Resistance of a conductor also depends on the resistivity of the material of the conductor. Resistance is directly proportional to the resistivity of the material of the conductor. Therefore, the resistivity will be the resistance of that conductor.
Consider a conductor of length l and cross sectional area A. Let the resistivity of the material be $\rho $. Then the resistance R of the conductor is given as $R=\dfrac{\rho l}{A}$.
Resistivity of a conductor is temperature dependent. As the temperature of the conductor is increased, its resistivity increases and when the temperature of the conductors is decreased, its resistivity decreases.
Since, resistance of a conductor is directly proportional to its resistivity, resistance also increases when the temperature is increased and decreases when the temperature is decreased.
Therefore, out of the options, the resistance of a conductor depends on its length, thickness (i.e. its cross sectional area) and temperature of the conductor. It does not depend on the humidity of the conductor.
Hence, the correct option is D.

Note: Do not confuse between resistance and resistivity of a conductor. Resistivity is material property. It depends only on the material of the conductor. It does not depend on the shape and size of the conductor. Whereas the resistance does depend on the shape and size of the conductor.
All the conductors of different sizes but made of the material will have the same value of resistivity but different values of resistances.