Question

A positron is an elementary particle identical to an electron except that its charge is +e. An electron and a positron can rotate about their center of mass as if they were a dumbbell connected by a massless rod.

a) What is the orbital frequency in rev/s for an electron and a positron 1.60 nm apart?

Answer 1

In this system the electric force provides the necessary centripetal force:

where, k is the Coulomb constant

q1 and q2 are the charges on the positron and electron respectively

d is the distance between them

v is the velocity with which they rotate.

The circumference of the orbit is given by:

Also, the time taken to cover this distance with velocity v is given by:

So, the orbital frequency can be given as the inverse of the orbital period:

PLEASE RATE.