The resistance of a wire is inversely proportional to its area and directly proportional to its length. When the length is tripled then resistance will also become.

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

Three times

One-third

Nine times

One-ninth

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Concept: It is important to remember that a wire's resistance is directly related to its length rather than being inversely proportional to its area. We can calculate the change in resistance by applying the formula,

R = ρl / A

Where, ρis the resistivity of the wire, L is the length of the wire and A is the cross sectional area of the wire.
That is, Resistance} =(Specific Resistivity Constant × Length of wire) } / Area of cross section of wire
RαL
So, if the length of the wire is tripled, the resistance will likewise increase by three times.
Rα1/A
In other words, when the wire is extended to three times its original length, its cross-section is reduced to one-third of its original cross-section. The aforementioned connection leads us to the conclusion that the present resistance is 9 times greater than the initial resistance.
Hence, option 1 is correct.

Result Producing online coaching for JEE/NEET of south India

Largest All India Test Series for JEE/NEET

Best Books for IIT JEE

Best Books for NEET

How to Join IIT after 10th