A proton and an alpha particle both enter a region of uniform magnetic field , moving at right angles to field . If the radius of circular orbits for both the particles is equal and the kinetic energy acquired by proton is  the energy acquired by the alpha particle will be:

A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross-section. The ratio of the magnetic fields  and , at radial distances and  respectively, from the axis of the wire is :

A square loop  carrying a current , is placed near and coplanar with a long straight conductor  carrying a current , the net force on the loop will be :      

A 250-turn rectangular coil of length  and width 1.25  carries a current of  and subjected to magnetic field of strength . Work done for rotating the coil by  against the torque is

An arrangement of three parallel straight wires placed perpendicular to plane of paper carrying same current 'I along the same direction is shown in fig. Magnitude of force per unit length on the middle wire '  ' is given by

Current sensitivity of a moving coil galvanometer is  and its voltage sensitivity (angular deflection per unit voltage applied) is . The resistance of the galvanometer is   

A metallic rod of mass per unit length  is lying horizontally on a smooth inclined plane which makes an angle of  with the horizontal. The rod is now allowed to slide down by flowing a current through it when a magnetic field of induction  is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is

A cylindrical conductor of radius  is carrying a constant current. The plot of the magnitude of the magnetic field,  with the distance, , from the centre of the conductor, is correctly represented by the figure :

A long solenoid of  length having 100 turns carries a current of . The magnetic field at the centre of the solenoid is : 

An infinitely long straight conductor carries a current of  as shown. An electron is moving with a speed of  parallel to the conductor. The perpendicular distance between the electron and the conductor is  at an instant. Calculate the magnitude of the force experienced by the electron at that instant.