List of top Physics Questions on Motion in a Magnetic Field asked in CBSE Class XII

Two particles of masses $m_1$ and $m_2$ having charges $q_1$ and $q_2$ respectively are projected with the same velocity in a region of uniform magnetic field $\vec{B}$ pointing vertically upward. If they describe circular paths as shown in the figure, one may conclude that :
An alpha particle (mass $6.4 \times 10^{-27}$ kg and charge $3.2 \times 10^{-19}$ C) having 8.0 MeV energy, enters a region of a uniform magnetic field of 0.5 T. If the field is directed perpendicular to the velocity of the particle, find the radius of the circular path described by the particle. Mention the condition under which the particle in this region (i) describes a helical path, and (ii) goes straight undeviated.
Two particles of masses \(m_1\) and \(m_2\) having charges \(q_1\) and \(q_2\) respectively are projected with the same velocity in a region of uniform magnetic field \(\vec{B}\) pointing vertically upward. If they describe circular paths as shown in the figure, one may conclude that :
An alpha particle (mass \(6.4 \times 10^{-27} \text{ kg}\) and charge \(3.2 \times 10^{-19} \text{ C}\)) having \(8.0 \text{ MeV}\) energy, enters a region of a uniform magnetic field of \(0.5 \text{ T}\). If the field is directed perpendicular to the velocity of the particle, find the radius of the circular path described by the particle. Mention the condition under which the particle in this region (i) describes a helical path, and (ii) goes straight undeviated.