A positron is an elementary particle identical to an electron except that its charge is . An electron and a positron can rotate about their center of mass as if they were a dumbbell connected by a massless rod.What is the orbital frequency for an electron and a positron 1.50 apart?

Respuesta :

Explanation:

According to the energy conservation,

          [tex]F_{centripetal} = F_{electric}[/tex]

            [tex]\frac{mv^{2}}{r} = \frac{kq^{2}}{d^{2}}[/tex]

           [tex]v^{2} = \frac{kq^{2}r}{d^{2}m}[/tex]

                 = [tex]\frac{9 \times 10^{9} N.m^{2}/C^{2} \times 1.6 \times 10^{-19} C \times 0.75 \times 10^{-9} m}{(1.50 \times 10^{-9}m)^{2} \times 9.11 \times 10^{-31} kg}[/tex]

                = [tex]8.430 \times 10^{10} m^{2}/s^{2}[/tex]

             v = [tex]\sqrt{8.430 \times 10^{10} m^{2}/s^{2}}[/tex]

                = [tex]2.903 \times 10^{5} m/s[/tex]

Formula for distance from the orbit is as follows.

               S = [tex]2 \pi r[/tex]

                  = [tex]2 \times 3.14 \times 0.75 \times 10^{-9} m[/tex]

                  = [tex]4.71 \times 10^{-9} m[/tex]

Now, relation between time and distance is as follows.

                T = [tex]\frac{S}{v}[/tex]

       [tex]\frac{1}{f} = \frac{S}{v}[/tex]

or,           f = [tex]\frac{v}{S}[/tex]          

                = [tex]\frac{2.903 \times 10^{5} m/s}{4.71 \times 10^{-9} m}[/tex]      

                = [tex]6.164 \times 10^{13} Hz[/tex]

Thus, we can conclude that the orbital frequency for an electron and a positron that is 1.50 apart is [tex]6.164 \times 10^{13} Hz[/tex].