We have a copper wire of resistance R . This wire is pulled so that its length is doubled (temperature remains constant ) . Find the new resistance of the wire in terms of its original resistance .
Answers
Electrical Resistance of a conductor is the opposition or obstruction offered to the passage of electrons by the material of the conductor.
Also, according to Ohm's law, the current in a circuit is proportional to the voltage: V= IR, R is the proportionality constant called resistance.
2. (i) We have R = ρl/A, where ρ is the resistivity of the material.
Let R1 = ρL/A and R2 = ρ.2L/(A/2) =4. ρL/A = 4R1.
So the new resistance is 4 times the original resistance.
(ii) Resistivity is independent of the length and area of cross section of the wire and hence it will not change.
The resistance of the wire is doubled the resistance of original resistance R
Therefore resistance is 2R
Because resistance depends on length and it is directly proportional to length