Answer:
D. 10 T
Explanation:
When a particle is moving in a magnetic field, the magnetic force provides the centripetal force that keeps the particle in circular motion.
The cyclotron period (the period the particle takes to complete one orbit) can be found to be
where
m is the mass of the particle
q is its charge
B is the magnetic field
As we see, the period is directly proportional to the mass of the particle.
In this problem, the second particle is ten times as massive as the first one:
m' = 10 m
while the speed is the same. So, the period of the second particle is