An electron is moving with a velocity $2\times {10}^{6}m/s$ along positive $x$ -direction in the uniform electric field of $8\times {10}^{7}V/m$ applied along positive $y$ -direction. The magnitude and direction of a uniform magnetic field (in tesla) that will cause the electrons to move undeviated along its original path is

A rectangular conducting loop of length $4\sqrt{2}m$ and breadth $4m$ carrying a current of $5A$ in the anti-clockwise direction is placed in the $xy$ -plane. The magnitude of the magnetic induction field vector $B$ at the intersection of the diagonal is $\left(\mathrm{u}\mathrm{s}\mathrm{e}\mathrm{ }{\mu }_0=4\pi \times {10}^{-7}N{A}^{-2}\right)$

A coil of $50$ turns carrying a current of $2\mathrm{A}$ in a magnetic field of $0.5\mathrm{T}$. The torque acting on the coil is