Frequency can be defined as the number of times an event occurs within a unit time. In the context of waves for example, frequency refers to the number of waves that pass through a point in a certain amount of time.
Mathematically, the frequency (f) is related to the time period (T) as-
f = 1/T
SI Unit of frequency is Hertz (Hz)
In the given example:
When T = 0.2 s; f = 1/0.2 = 5 Hz
When T = 0.5 s; f = 1/0.5 = 2 Hz
As T increases, f decreases
Ans: B) It would decrease