A player with 3 meter long iron rod runs toward east with a speed of `30km//hr` . Horizontal component of eath's magnetic field is `4xx10^(-5)Wb//m^(2)` . If he runs with the rod in horizontal and vertical position, then the potential difference induced between the two ends of the rod in the two cases will be

Options

A. zero in vertical position, `1xx10^(-3)V` in horizontal position
B. `1xx10^(-3)V` in vertical position, zero in horizontal position
C. zero in both positions
D. `1xx10^(-3)V` in both positions

Answer

B

Explanation

`B_(h)=4xx10^(5)T` from south to north i.e.,
`vec(B)_(h)=4xx10^(-5)hatjT`
`vec(v)30xx(5)/(18)hati=(25)/(3)im//sec`
Horizontal Position: `vec(l)=3hatj` , `e=0`
Vertical position: `vec(l)=3hatk` , `e=B_(h)vl=4xx10^(-5)xx(25)/(3)xx3`
`=10^(-3)V`