Question

A charged particle moving in a uniform magnetic field loses 4% of its kinetic energy. The radius of curvature of its path changes by

• A. \(2\%\)
• B. \(4\%\)
• C. \(10\%\)
• D. 12%

Hint:

In magnetic fields: • Radius ∝ v • Kinetic energy ∝ v²

Answer 1

The Correct Option is A

Step 1: Radius of circular motion: r = (mv)/(qB)
Step 2: Since K ∝ v², a 4% decrease in kinetic energy gives: (Δ v)/(v) = (1)/(2) × 4% = 2%
Step 3: Radius depends linearly on velocity, hence radius decreases by 2%.