Practice question

Given: An electron moves at 6.5 × 10⁶m/s perpendicular to a field of 0.2 T . What is the radius of its path? (Mass = 9.1 × 10⁻³¹kg, charge = 1.6 × 10⁻¹⁹C ) Formula: r = mv/qB. Substitution & Calculation: r = frac9.1 × 10⁻³¹ × 6.5 × 10⁶¹.6 × 10⁻¹⁹ × 0.2 = frac5.915 × 10⁻²⁴³.2 × 10⁻²⁰= 1.848 × 10⁻⁴m approx 0.0185 cm . Final Result: The computed value matches expected outcome and confirms correct choice as per latest NCERT 2026-27.