A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in figure
(##HCV_VOL2_C38_E01_033_Q01##)

Options

A. `(10mg)/(5)`
B. `(9mg)/(5)`
C. `(11mg)/(5)`
D. `(12mg)/(5)`

Answer

C

Explanation

An uniform …………….
`I_(c )=(2)/(3)mR^(2)`
`I_(cm)=(5)/(12)mR^(2)`
When `omega` is maximum
`mg(R )/(2)=(1)/(2)((5)/(12)mR^(2))omega^(2)`
`omega^(2)(R )/(2)=(6g)/(5)`
`N_(max) = mg+m.(6g)/(5)`
`N_(max) = (11mg)/(5)`