Question

A wire has a resistance of 16 ohm it is drawn to double its length and then cut it into four equal parts these parts are connected in parallel and series find new resistance

Answer 1

Answer:

4

Explanation:

consider volume to be equal in both the cases

V1 = V2

so A1 * l1 = A2 * l2

since the length has been doubled l2= 2l1

it implies A1= 2A2

resistance = restivity *length /area

new res/prev res = 2 * length / (A1/2)

length /A1

new res = prev res * 4

which implies new resistance to be 64 ohms

since you have cut into 4 equal parts now each wire resistance would be 16 ohms each

now 4 wires of 16 ohms are connected into parallel

therefore equivalent resistance is 16/4 which is 4 ohms