An electron of energy 1800 eV describes a circular path in magnetic fi...
Given:
Energy of the electron, E = 1800 eV
Flux density of the magnetic field, B = 0.4 T
Charge of the electron, q = 1.6 x 10^-19 C
Mass of the electron, me = 9.1 x 10^-31 kg
To find:
Radius of the circular path, r
Formula used:
The equation for the radius of the circular path of a charged particle in a magnetic field is given by:
r = (me * v) / (q * B)
Where v is the velocity of the charged particle.
Derivation:
1. We can calculate the velocity of the electron using the formula:
E = (1/2) * me * v^2
Rearranging the equation, we get:
v^2 = (2 * E) / me
Substituting the given values, we have:
v^2 = (2 * 1800 eV) / (9.1 x 10^-31 kg) = 3.96 x 10^21 m^2/s^2
Taking the square root, we find:
v = 1.99 x 10^10 m/s
2. Now, substituting the values of me, v, q, and B into the formula for the radius of the circular path, we get:
r = (me * v) / (q * B)
= (9.1 x 10^-31 kg * 1.99 x 10^10 m/s) / (1.6 x 10^-19 C * 0.4 T)
= 3.58 x 10^-4 m
Therefore, the radius of the circular path of the electron is 3.58 x 10^-4 m, which corresponds to option B.