Question

what is the resistance if the length of a conductor is doubled ​

Answer 1

Answer:

The resistance of a body is the property to resist the flow of electrons.

Resistance is depends on the length of the conductor, material of conductor and the area of cross section.

It is :

1. Directly proportional to length of conductor.
2. Indirectly proportional to area of cross section.
3. And also depends on the material of conductor.

Now, if the length of the conductor is doubled, then as resistance is directly proportional to length of conductor, so the resistance will also increase.

The resistance will also get doubled if the length of the conductor is doubled.

Answer 2

16 ohm

Explanation:

According to the given question,

Initial

Let initial, Resistance = R

Length = L

Area of cross section = A

And we are asked to find the new resistance if length is doubled and area is halved.

Final

Let new resistance = R'

Length = L' = 2L

Area of cross section = A' = A/2

So we know that resistivity of the given conductor is same.

And we also know that , R = pL/A

Where p = resistivity ( which is constant here)

L = length of the wire

A = Area of cross section

R = Resistance

Therefore,

R'/R = L' × A/ L × A'

(Resistivity is same , so it gets cancel out)

R'/R = 2L × A/ L × (A/2)

R'/R = 4 L×A/L×A

R'/R = 4

R' = 4R

By putting the value of R = 4 ohm.

R' = 4×4

R' = 16 ohm ans.