Question

A wire has a resistance R . what will be its resistance if it is stretched so that its length is doubled​

Answer 1

Answer:

4r is the resistance. hope you understand please mark brainliest.

Answer 2

Answer: Let the R be resistance, l be the length of the wire.

According to question,

Length is doubled means now it is 2l and area gets decreased by 2 times.

By the formula of resistivity,

⇒ Resistivity = (Area × Resistance)/length

⇒ Resistance = (Resistivity × length)/Area

(After Changing length to 2l)

⇒ R = (p×2l)/A/2

⇒ R = (p×4l)/A

As we know that Resistance is directly proportional to length then,

→R∝l

→R∝4l        [Thererefore, R is increased by 4 times.]