Magnetic Field Objectives (HCV)

1. A particle moves in a region having uniform magnetic field and a parallel, uniform electric field. At some instant, the velocity of the particle is perpendicular to the field direction. The path of the particle will be

a) a straight line
b) a circle
c) a helix with uniform pitch
d) a helix with non-uniform pitch

2. If a charged particle goes unaccelerated in a region containing electric and magnetic fields,

a) \vec{E} must be perpendicular to \vec{B} .

b) \vec{v} must be perpendicular to \vec{E} .

c) \vec{v} must be perpendicular to \vec{B} .

d) E must be equal to vB.

3. Let \vec{E} and \vec{B} denote electric and magnetic fields in a frame S and \vec{E}' and \vec{B}' in another frame S' moving with respect to S at a velocity \vec{v}. Two of the following equations are wrong. Identify them.

a) B_{y}' =B_{y}+\frac{vE_{z}}{c^{2}}

b) E_{y}' =E_{y}-\frac{vB_{z}}{c^{2}}

c) B_{y}' =B_{y}+vE_{z}

d) E_{y}' =E_{y}+vB_{z}

Note: Please just don't post the answers. Answers are available. These questions are doubts so please provide some explanation. [1]