An electron having kinetic energy moves in a circular orbit of radius

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Magnetism and Electromagnetism · Magnetism and Electromagnetism

Problem

An electron having kinetic energy

K

moves in a circular orbit of radius

R

, perpendicular to a uniform magnetic field. If its kinetic energy is doubled and the magnetic field is tripled, the radius becomes (a)

\frac{2R}{3}

(b)

\frac{\sqrt{2}}{3}R

(c)

\sqrt{\frac{2}{3}}R

(d)

\frac{2}{\sqrt{3}}R