Question

Following charged particles are projected perpendicular to a uniform magnetic field with same velocity. Which one will experience maximum force?

• A. electron
• B. proton
• C. \(\alpha\) particle
• D. deuteron

Hint:

\(F = qvB\) with same \(v,B\); largest charge wins, and the \(\alpha\) particle carries \(2e\).

Answer 1

The Correct Option is C

Step 1: Recognize the force law \(F = qvB\) for perpendicular projection.
With identical \(v\) and \(B\), force is directly proportional to charge magnitude: \(F \propto q\).
Step 2: List charge in units of elementary charge \(e\).
electron \(= 1e\), proton \(= 1e\), deuteron (one proton + one neutron) \(= 1e\), alpha (two protons + two neutrons) \(= 2e\).
Step 3: Rank the forces.
Three particles tie at \(F = evB\); the alpha particle gives \(F = 2evB\), which is the largest.
Step 4: Therefore the alpha particle feels twice the force of the others.
\[\boxed{\alpha\text{ particle}}\]