Physics, asked by vikaries9863, 9 months ago

A cylindrical wire 4.0 m long has a resistance of 31ohms and is made of same metal of resisitvity 40000 ohm m what is the radius of cross section of wire?

Answers

Answered by mvm9363

Answer:

Logic dictates that for any cylindrical resistor the resistance R (ohms) is proportional to the length L and inversely proportional to the cross sectional area, which is pi.r^2

Where r is the radius.

The constant of proportionality is called resistivity and has symbol “rho”. Here the length is given in meters, so we can take it that rho value given above is in ohm-m.

So we have R=(rho.L/(pi.r^2)

Re-arranging we have:

r=SqRoot(rho.L/(pi.R)

Giving the radius in m

Explanation:

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