Question

21. Half part of a wire of resistance R is stretched to
make it 1% longer and remaining half is stretched
to make it 2% longer. The new resistance of the
wire is nearly
(1) 1.04 R
(2) 1.03 R
(3) 1.06 R
(4) R​

Answer 1

Step-by-step explanation:

Given  

21. Half part of a wire of resistance R is stretched to make it 1% longer and remaining half is stretched to make it 2% longer

We know that according to question we get

1 % l / 2 = l / 200

2% l/2 = l / 100

Total charge = 3l / 200

So percentage will be 3l / 200 / l x 100  

                               = 1.5%                      

We know that R = ρ l / A

So ΔR / R = Δl / l + ΔA / A

So ΔR = R(0.015 + 0.015)

           = R(0.03)

Now R’ = R + 0.03 R

            = 1.03 R

Similar reference link will be

https://brainly.in/question/1363349