Define periodic time and frequency. State their $SI$ units,dimensional formulas,and the relationship between them.

(N/A) Periodic Time: The smallest interval of time after which the motion is repeated is called its period. It is the time required to complete one oscillation. It is denoted by $T$. Its $SI$ unit is second $(s)$. The dimensional formula is $[M^0 L^0 T^1]$.
Frequency: The number of oscillations completed in one second is called frequency. It is denoted by $f$ or $\nu$. Its $SI$ unit is $Hz$ (Hertz) or $s^{-1}$. The dimensional formula is $[M^0 L^0 T^{-1}]$.
Relationship: Frequency is the reciprocal of periodic time. Mathematically,$f = \frac{1}{T}$ or $T = \frac{1}{f}$.