Concept:When charged particles enter a transverse electric or magnetic field, their path is deflected. The radius of curvature (and thus the amount of deviation) depends on the particle's mass, velocity, and charge.
Formula:$$ r = \frac{mv}{qB} $$
Solution:- Deflection is inversely proportional to mass. A higher mass creates a larger radius of curvature (less visible deviation/bending).
- An alpha particle (mass \(\approx 4\text{ amu}\)) is nearly 7,300 times heavier than a beta particle (an electron).
- Due to its massive inertia, the alpha particle strongly resists changes in its momentum, causing it to deviate much less than the lightweight beta particle, despite carrying twice the charge.
Why other options are incorrect:Option A is factually inverted. Option C is false; alpha particles generally travel at \(0.05c\) while beta particles can approach \(0.9c\).
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