1.

A piece of wire of resistance 10 ohm is drawn out so that its length is increased to three times its original length. Calculate the new resistance.

Answer»

Solution :`""`Specific resistance `(rho)=(RA)/l`
`""R=(rhol)/A`
When the length is increased by three and then the AREA of CROSS SECTION is reduced by three
`"Resistance of wire R"=10Omega`
`"New resistance" R^(.)=(rho(3l))/((A//3))`
`""=rho(3l) times 3/A`
`""R^(.)=(9rhol)/A`
`""R^(.)= 9 times R=9 times 10`
`""R^(.)=90 Omega`


Discussion

No Comment Found

Related InterviewSolutions