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Which statement is true regarding the factors affecting the resistance of a conductor?
Resistance is inversely proportional to the length of the conductor
Resistance is directly proportional to the area of cross-section
Resistance is directly proportional to the resistivity of the material
Resistance does not depend on temperature
Resistance is directly proportional to the resistivity of the material
The resistance of a conductor is directly proportional to its resistivity, which is an intrinsic property of the material. This means materials with higher resistivity offer greater opposition to the flow of electric current under identical geometric conditions.
The resistance of a conductor is directly proportional to its resistivity, which is an intrinsic property of the material. This means materials with higher resistivity offer greater opposition to the flow of electric current under identical geometric conditions.
Think of resistivity as the 'thickness' or 'viscosity' of a liquid; even if you have a wide pipe, a more viscous liquid will be harder to push through than water, just as a material with high resistivity is harder for electrons to flow through.
Remember 'R-L-A-R': Resistance is directly proportional to Length, inversely to Area, and directly to Resistivity.
R=╧БAlтАЛ тАФ Where R is resistance, ╧Б is resistivity, l is length, and A is cross-sectional area.
Resistance is defined by the formula R=╧БAlтАЛ. Here, R is directly proportional to the material property resistivity (╧Б), directly proportional to length (l), and inversely proportional to the area of cross-section (A). As electrons drift through a conductor, they collide with ions in the lattice; materials with higher resistivity increase the frequency or impact of these collisions, thereby increasing resistance.
Resistivity (╧Б) depends solely on the nature of the material and temperature.
Resistance increases with an increase in length because electrons undergo more collisions.
Resistance decreases with an increase in cross-sectional area as more paths are available for electron flow.
Selection of materials for heating elements (high resistivity).
Selection of materials for electrical wiring (low resistivity).
Resistivity is measured in Ohm-meters (╬йтЛЕm).
Option A is incorrect because RтИЭl.
Option B is incorrect because RтИЭA1тАЛ.
Option D is incorrect because R typically increases with temperature for conductors.
C is correct тАФ Resistance is directly proportional to the resistivity of the material.
Always remember that resistance is a physical property of the device, whereas resistivity is an intrinsic property of the substance itself.