In a region there exists a magnetic field `B_(0)` along positive x-axis. A metallic wire of length 2a, one side along x-axis and one side parallel of y-axis is rotates about y-axis with a angular velocity. Then at the instant shown

Options

A. Potential difference across PQ is 0
B. Potential difference across PQ is `1/2 B_(0)omega a^(2)`
C. Potential difference across QR is `1/2 B_(0)omega a^(2)`.
D. Potential difference across QR is `B_(0)omega a^(2)`.

Answer

A, D

Explanation

PQ is parallel to magnitude field, hence no emf is induced in it. QR is `_|_^(r)` perpendicular to magnetic field. Induced emf =`Bv1=B_(0)omega a^(2)`.