An electron travels at 2.0 x 107 m/s in a plane perpendicular to a 0.1 T magnetic field. What is the radius and period of the electron? (hint: recall centripetal force and tangential velocity)

r = 0.001137 m = 1.137 mm

T = 3.57 x 10⁻¹⁰ s

Explanation:

In order for the electron to remain in a fixed circle centripetal force must be equal to the magnetic force:

where,

r = radius = ?

m = mass of electron = 9.1 x 10⁻³¹ kg

v = speed of electron = 2 x 10⁷ m/s

q = charge on electron= 1.6 x 10⁻¹⁹ C

B = Magnetic Fild Strength = 0.1 T

θ = Angle between velocity and magnetic field = 90° (perpendicular)

r = 0.001137 m = 1.137 mm

Now, for the period of the electron:

where,

T = Time period required o cover a distance equal to cirumference = ?

T = 3.57 x 10⁻¹⁰ s

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )

i would say