an electron with velocity v=3x10 to the power 7 m/s describes a circular path in a uniform magnetic field of 0.2T perpendicular to it calculate the radius of the path?

ma=F

mv²/R=qvBsinα
circular path = >sinα = 90⁰
q=e= e =1.6•10⁻¹⁹ C,
m=9.1•10⁻³¹ kg
R=mv/eB =
=9.1•10⁻³¹•3•10⁷/1.6•10⁻¹⁹•0.2 = …