The earth's magnetic field at a place with zero declination is `3xx 10^(-4)` T. The angle of dip at that place is `30^@`. A conducting rod is kept is north south direction and is moved at a constant speed of 1 m/s towards east. The emf induced in the rod is ...... (The length of the rod is 10 cm.)

Options

A. `15muV`
B. `15mV`
C. 0.15V
D. 1.5V

Answer

A

Explanation

`vecl` and `vecv` are mutually perpendicular
`therefore veclxxvecv=lv hatn`, where `hatn` is unit vector in the downward direction.
`hatn` makes an angle of `60^@` with `vecB`.
`therefore epsilon=vecB.(veclxxvecn)=vecB.lvhatn`
=Blv cos`theta`
=Blv cos `60^@`
`=3xx10^(-4)xx0.1xx1xx1/2`
`=0.15xx10^(-4)=15xx10^(-6)` V
`therefore epsilon=15muV`