Question

A metal rod `1/(sqrt(pi))` m long rotates about one of its ends in a plane perpendicular to a magnetic field of induction `4 xx 10^(-3)T`. If the emf induced between the ends of the rod is 16 mv, then the number of revolutions made by the rod per second is

Answer 1

`E=(1)/(2)Bomegal^(2)`
`implies" "16xx10^(-3)=(1)/(2)xx4xx10^(-3)xxomegaxx((1)/(sqrt(pi)))^(2)`
`implies" "16xx10^(-3)=(1)/(2)xx4xx10^(-3)xxomegaxx(1)/(pi)`
`implies" "16xx10^(-3)=2xx10^(-3)xx2pinxx(1)/(pi)`
`implies" "n=(16xx10^(-3)xx2xx2)/(4xx10^(-3)xx2xx2)`
`implies" "n=4`.