A horizontal semi-circular wire of radius r is connected to a battery through two similar springs X and Y to an electric cell, which sends current I through it. A vertically downward uniform magnetic field B is applied on the wire, as shown in the figure. What is the force acting on each spring?
Find the equivalent capacitance between A and B of the following arrangement :
A golf ball of mass 50 gm placed on a tee, is struck by a golf-club. The speed of the golf ball as it leaves the tee is 100 m/s, the time of contact on the ball is 0.02 s. If the force decreases to zero linearly with time, then the force at the beginning of the contact is
Three concentric metallic shells A, B and C of radii a, b and c (a < b < c) have surface charge densities +$$\sigma$$, $$-$$$$\sigma$$ and +$$\sigma$$ respectively. The potential of shell B is