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50 turns of a wire of diameter 1mm is wo...

50 turns of a wire of diameter 1mm is wound on a cylinder of radius 5 cm. If the specific resistance of the materical of the wire is `4.5xx10^-6Omegam`, then its resistance is

A

`9kOmega`

B

`900Omega`

C

`250 Omega`

D

`90Omega`

Text Solution

Verified by Experts

The correct Answer is:
D
`n=50,r=0.5mm,a=5cm,rho=4.5xx10^-6Omega m, R=?`
`R=(rho^l)/(A)=(rho^l)/(pir^2)=(rho.2pia.n)/(pi r^2)`
`therefore R=(rho2an)/(r^2)=(4.5xx10^-6xx2xx5xx10^-2xx50)/(0.25xx10^-6)`
`therefore R=9 0 Omega`
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