1) When a charged particle is in a region of magnetic field, which of the following is not a necessary condition for the particle to experience a magnetic force?

2) The length of VW, WX, XY and YZ are 10.0 cm each. Find the net force on the segment of wire, VWXYZ, in the figure below if the strength of the magnetic field B is 0.40 T and the current I flowing through the wire is 5.0 A.

3) A metal rod, length L and mass m, is placed on a very long and smooth plane, which makes an angle of θ to the horizontal. The rod is connected to a battery of e.m.f. E through light and flexible wires. The rod is released from rest at the top of the plane and moves in a uniform magnetic field B that is vertically downwards everywhere.

What is the magnitude of B required to keep the rod moving at constant velocity?

4) The diagram shows an electron beam entering the region between two metal plates in which there are uniform electric and magnetic fields.

If the speed of the electrons in the beam is 6.00 × 105 m s⁻¹, and the strength of the magnetic field is 0.238 mT, what is the magnitude and direction of the electric field that will allow the beam to pass through undeflected?

5) P and Q are two ions with masses m_P and m_Q respectively. They have the same charge q and the work done on both charges after passing through an applied p.d. of V is qV. Subsequently, P and Q enter a magnetic field B.

The radius of the path of ions P and Q is r_P and r_Q respectively. What is the ratio of r_Q / r_P?