Find the magnitude of the force on an electron that is travelling with velocity 2 x 10^4 ms^(-1) in the x direction through a uniform magnetic field of strength 2T in the y direction.

This question tells us we only need to consider the magnitude of the force, and since the magnetic field and electron's velocity are perpendicular, we can simply use the equation

F = Bqv.

We have B = 2 T, q = 1.6 x 10-19 C (the charge of an electron) and v = 2 x 104 ms-1.

Substituting these values into the equation gives 

F = 2 * (1.6  x 10-19 ) * (2 x 104) = 6.4 x 10-15 N   (Remember your units!)

SH

Related Physics A Level answers

All answers ▸

Bismuth-208, which has an atomic mass of 208u and 83 protons in the nucleus, decays through the emission of 2 alpha particles and a beta-positive particle. What isotope results from this decay?


An exo-planet orbits its local star, of mass 2.00x10^30kg, in a steady circular orbit of radius 8.00x10^8km. Calculate the orbital period of the star, in years.


A body is moving at 70km/h and has a mass of 130kg, calculate its maximum kinetic energy.


Find an expression for the escape velocity of a test object.