Answer:
a)0.364 ns
b)1.43 x 10^-3
c)163.21 x 10^-5 m
Explanation:
mass of the positron is m=9.1 x 10^-31 kg
charge is q=1.6 x 10^-19 C
strength of the magnetic field is B=0.0980 T
kinetic energy is K=2.30 keV=2.30 x 10^3 x 1.6 x 10^-19 J
0.5mv^2=6.68 x 10^-16 J
0.5 x 9.1 x 10^-31 x v^2 =3.68 x 10^-16
v=2.84 x 10^7 m/s
a)the period is T=2πm/qB
                          =2π(9.1 x 10^-31 )/1.6 x 10^-19x 0.0980
                          =0.364 ns
b) pitch is p=vcosθ(2πm/qB)
                   =2.84 x 10^7x cos82(0.364 x 10^-9)
                   =1.43 x 10^-3
c) radius is r=mvsinθ/qB
                   =(9.1 x 10^-31 )2.84 x 10^7x sin82/1.6 x 10^-19x 0.098
                    =163.21 x 10^-5 m