Answer:
Speed of the proton is

Step-by-step explanation:
It is given that,
Magnetic field, B = 1.35 T
Radius of circular path, r = 0.072 m
The centripetal force is balanced by the magnetic force such that,


q and m is the charge and mass of a proton respectively


So, the speed if the proton is
. Hence, this is the required solution.