Physics
(a) How does the resistance of a wire depend on it's radius? Explain your answer.
(b) Two copper wires are of same length, but one is thicker than the other. Which will have more resistance?
Current Electricity
68 Likes
Answer
(a) In a thick conductor, electrons get a larger area of cross section to flow as compared to a thin conductor, therefore a thick wire offers less resistance. The resistance of a conductor is inversely proportional to it's area of cross section (a), normal to the direction of flow of current i.e.,
R ∝
Hence,
R ∝
where r is the radius of the wire.
Hence, resistance of a wire is inversely proportional to the square of the radius of the wire.
(b) As we have seen above that the resistance of a conductor is inversely proportional to it's area of cross section (a), normal to the direction of flow of current. Hence, the thin wire, will offer more resistance as it's area of cross section is less.
Answered By
44 Likes
Related Questions
Draw an I-V graph for a linear resistor. What does it's slope represent?
Draw a V-I graph for a conductor at two different temperatures. What conclusion do you draw from your graph for the variation of resistance of conductor with temperature?
What is an ohmic resistor? Give one example of an ohmic resistor. Draw a graph to show it's current–voltage relationship. How is the resistance of the resistor determined from this graph?
What are non-ohmic resistors? Give one example and draw a graph to show it's current-voltage relationship.