A metallic rod of length 'l' is tied to a string of length 2l and made to rotate with angular speed w on a horizontal table with one end of the string fixed. If there is a vertical magnetic field 'B' in the region, the e.m.f. Induced across the ends of the rod is

Options

A. `(2Bomegal^(2))/2`
B. `(3Bomegal^(2))/2`
C. `(4Bomegal^(2))/2`
D. `(5Bomegal^(2))/2`

Answer

D

Explanation

`e=underset(2l)overset(3l)int(omegax)Bdx=Bomega([(3l)^(2)-(2l)^(2)])/2`
`=(5Bl^(2)omega)/2`