Question

A piece of wire of resistance is drawn out so that its length is increased to twice its original length calculate the resistance of the wire is the new situation?​

Answer 1

Answer:

Explanation:

Here ;

At the initial case for the given situation we have the formula and that is

 

   $Resistance( R1) = \frac{Resistivity *length}{Area}$   =  $\frac{Resistivity * l}{A}$   ------ (1)

At the second case its length is double than the original length ( i.e. $l^{'}$ = 2l)

   $Resistance(R2) =\frac{Resistivity * l^{'} }{A}$

                       $R2 = \frac{Resistivity * 2l}{A}$

                       $R2 = 2\frac{Resistivity * l }{A}$

 Therefore,    R2 = 2 R1          ( From i )

Hence , the resistance of the wire is increased by 2 times the initial resistance.