# In a uniform magnetic field with an induction of 80 mT, an electron flies in at a speed of 40 Mm / s

**In a uniform magnetic field with an induction of 80 mT, an electron flies in at a speed of 40 Mm / s perpendicular to the lines of induction. What is the force acting on an electron in a magnetic field.**

An electrically charged particle that moves in a magnetic field is affected by the Lorentz force, which is determined by the equation:

Fl = q * v * B * sinα,

where q is the electric charge of the particle, v is the speed of the particle, B is the magnetic field induction, α is the angle between the velocity vector and the magnetic induction vector.

If the particle moves perpendicular to the lines of induction of the magnetic field, then α = 90о, respectively, sinα = sin90о = 1.

Since in our case the electron is moving, then q = | e | = 1.6 * 10-19 (Cl).

Particle velocity v = 40 (Mm / s) = 40 * 10 ^ 6 (m / s) = 4 * 10 ^ 7 (m / s).

Induction B = 80 (mT) = 80 * 10 ^ -3 (T) = 8 * 10 ^ -2 (T).

Let’s calculate the Lorentz force acting on the electron:

Fl = q * v * B * sinα = 1.6 * 10 ^ -19 * 4 * 10 ^ 7 * 8 * 10 ^ -2 = 51.2 * 10 ^ -14 (H).

Answer: F = 51.2 * 10-14 (H).