Reason
As velocity increases time taken by ion increases.
Assertion
The ion cannot move with a speed beyond a certain limit in a cyclotron.
A
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B
Assertion is correct but Reason is incorrect
C
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
D
Both Assertion and Reason are incorrect
Correct option is C. Assertion is correct but Reason is incorrect
Time taken is independent of velocity and radius of path.
However, maximum velocity will be given by
$$v_{max}=\dfrac{q BR}{m}$$
where $$R$$ is radius of Dee’s.