Question

65. A length of wire is bent into a closed loop and a magnet is plunged into it, inducing a voltage and, consequently, a current in the wire. A second length of wire, twice as long, is bent into two loops of wire, and a magnet is similarly plunged into it. Twice the voltage is induced, but the current is the same as that produced in the single loop. Why

Answer 1

The resistance of the second wire is two times that of the first wire. Even though the voltage doubles, current still remain the same.

Step-by-step explanation:

The voltage induced is directly proportional to the number of loops of the wire. Resistance is directly proportional to the length of the wire as long as all other parametersare constant in the formula R=PL/A. The second wire has twice the length and twice the number of turns than the first wire.

Answer 2

Resistance of the second wire is twice the first wire.

Step-by-step explanation:

Let us first see the formula of resistance;

R = pxL/A

Here L is the lenght of the wire, A the area and p is the resistivity of wire.

As we are given that the length of second wire is double than that of the first wire, hence the resistance of second wire would be double.

Since we have two loop in second case, inducing double voltage but as resistance is doubled so the current would remain same according to ohms law

I = V/R