Question

The resistance of a conducting wire x of length 1m is 5ohm . Calculate the resistance of wire made by the same material whose length is 4 time s and area of cross section is 5times that of wire x .at same Temperature.

Answer 1

Answer:

4 ohm

Explanation:

R=kl/A

In the first case R=5 ohm

l=1m

In the second case let R=R1

l=4l, A=5A

By taking the ratio R/R1, we get

R1/R=4/5

R1=4 ohm

Answer 2

Answer:

4 Ω

Explanation:

rho = RA/L

In this first case, R= 5 Ω      length = L    Area = A

R = rhoL/A

5 = rho(1)/A

rho = 5A

Note : There's no temperature change

In the second case, R = ?     Length = 4L     Area = 5A

R = rho(4)/5A

  = 4/5 x rho/A

  = 4/5 x 5A/A

  = 4/5 x 5

R = 4Ω

Hope this helps

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