A uniform magnetic field acts perpendicular to the velocity of an electron. The electron follows a circular path of radius 2 cm. If its speed is doubled, what is the radius of the new circular path?
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A uniform magnetic field acts perpendicular to the velocity of an electron. The electron follows a circular path of radius 2 cm. If its speed is doubled, what is the radius of the new circular path?

G1 Physics · Accepted Answer

Step 1: The radius in a uniform magnetic field is r = mv/(|q|B). Step 2: For the same particle and same B, r ∝ v. Step 3: Doubling v doubles r, giving r₂ = 2 × 2 cm = 4 cm. Final answer: (C) 4.0 cm.