a) Derive the expression for the torque acting on the rectangular current carrying coil of a galvanometer. Why is the magnetic field made radial ?
b) An α-particle is accelerated through a potential difference of 10 kV and moves along x-axis. It enters in a region of uniform magnetic field B = 2×10–3 T acting along y-axis. Find the radius of its path.(Take mass of α-particle = 6·4×10–27 kg)
