(Solved): B4. (a) A non-conducting sphere has a mass of 0.050 kg and a radius of 0.200 m. A flat, compact co ...

B4. (a) A non-conducting sphere has a mass of 0.050 kg and a radius of 0.200 m. A flat, compact coil of wire with 5 tums is wrapped tightly around it, with each turn concentric with the sphere. The sphere is placed on an inclined plane that slopes downwards to the left, making an angle with the horizontal so that the coil is parallel to the inclined plane as shown in Figure B4(a). A uniform magnetic field of 0.500 T vertically upwards exists in the region of the sphere. What current in the coil will enable the sphere to rest in equilibrium on the inclined plane? (Hint: Moment = Force (F) x moment am (d)] (5 marks) 6) A uniform magnetic field of magnitude 0.200 T is directed along the positive x-axis. A positron (charge of positron, qpositre = +1.60 x 10-C and mass of positron, Mponita = 9.11 x 10 kg) moving at a speed of 1.00 x 10' m's enters the field in a direction that makes an angle ofe= 85.0° with the x-axis. The motion of the particle is expected to be a helix. Calculate the pitch p and the radius r of the trajectory as shown in Figure B4(6) (5 marks) Figure B4) Figure B4b)