Question

A conducter wire having the resistance 5ohm
if its length became double and area of
cross section becomes half then find the
new resistance of
wire​

Answer 1

Answer:

Explanation:

Hey there !

Solution:

Formula to be used:

Resistance = Resistivity × Length / Area

Given that the length is doubled. So let the original Length be 'x' and area of cross section be 'y'

So Old resistance = Resistivity × x / y => Equation 1

We know that, If length of a conductor doubles, then the area of the cross-section becomes half as they are inversely proportional.

Hence the area of cross section will become y / 2

So Resistance = Resistivity × 2x / y / 2

=> New Resistance = 2 × 2 × Resistivity × x / y

=> New resistance = 4 Old resistance. ( From Equation 1 )

Hence the new resistance = 4 × 5 = 20 Ω

Hope my answer helped !

Answer 2

Hey there !

Solution:

Formula to be used:

Resistance = Resistivity × Length / Area

Given that the length is doubled. So let the original Length be 'x' and area of cross section be 'y'

So Old resistance = Resistivity × x / y => Equation 1

We know that, If length of a conductor doubles, then the area of the cross-section becomes half as they are inversely proportional.

Hence the area of cross section will become y / 2

So Resistance = Resistivity × 2x / y / 2

=> New Resistance = 2 × 2 × Resistivity × x / y

=> New resistance = 4 Old resistance. ( From Equation 1 )

Hence the new resistance = 4 × 5 = 20 Ω

Hope my answer helped !