A wire has resistance of `10Omega`. If it is stretched by 1/10th of its length, then its resistance is nearly

Options

A. `9Omega`
B. `10Omega`
C. `11Omega`
D. `12Omega`

Answer

D

Explanation

Resistance of wire `R = rho l//A =10 Omega,` New length,
`l_(1)=l+l//10=11//10`
`therefore` New are, `A_(1)=Al // l_(1)=(10A)/(11)`
`therefore` New resistance, `R_(1)=rho l_(1)//A_(1)=rho(11//10)//(10//11)A`
`= (121 rho l)/(100 A)=(121)/(100)xx10`
`= 12.1 Omega`