Question

Please solve it.....

Answer 1

resistance = pl/a ... in first case 1= pl/a and when wire is stretched length gets doubled but area becomes half .. so applying the same formula we get new resistance as 4 ohm

Answer 2

When you stretch a given wire

First the length increases by two,

Resistance and length are directly proportional

Hence resistance is doubled

Resistance = 1 * 2 = 2 ohm

Second the area of cross section decreases by half,

Resistance and area of cross section are inversely proportional

Hence resistance further doubles

Resistance = 2 * 2 = 4 ohm