An electron flies into a uniform magnetic field with an induction of 90 mT perpendicular to the lines of magnetic
An electron flies into a uniform magnetic field with an induction of 90 mT perpendicular to the lines of magnetic induction at a speed of 4000 km / s What is the radius of its trajectory
B = 90 mT = 0.09 T.
q = 1.6 * 10-19 Cl.
∠α = 90 °.
V = 4000 km / s = 4000000 m / s.
m = 9.1 * 10-31 kg.
R -?
Since an electron is a charged particle with a charge q = 1.6 * 10-19 C and a mass m = 9.1 * 10-31 kg, then in a magnetic field it is acted upon by the Lorentz force Fl and Newton’s 2 law is valid.
Fl = q * V * B * sinα.
m * a = q * V * B * sinα.
We express the centripetal acceleration by the formula: a = V2 / R.
m * V2 / R = q * V * B * sinα.
R = m * V * sinα / q * B.
R = 9.1 * 10-31 kg * 4000000 m / s * sin90 ° / 1.6 * 10-19 C * 0.09 T = 0.00025 m.
Answer: in a magnetic field, the radius of the trajectory is R = 0.000025 m.