Question

A wire of given material having length
' L ' and area of cross - section ' A ' has a resistance of 6 ohm . What should be the resistance of another wire of same material having length 1/3 and are of cross section 3 A ?

Answer 1

Answer:

1 ohm

Explanation:

Resistance = p l/a [ p is constant]

For first wire length = l and area of croos section = a

Resistance = p l/a = 4 ohm [given]

For second wire length = l/2 and area of cross section = 2a

Resistance = p (l/2) / 2a

                  = p l/4a

                  = p l/a * 1/4 [p l/a = 4 ohm]

                  = 4*1/4 =  1 ohm

The resistance of second wire = 1 ohm