If a wave has a frequency of 2 HZ what would it be in seconds?

Frequency is not a length of time. It's exactly the opposite.

Frequency tells you how often something happens. In fact,

the unit 'Hz' means 'per second'.

Frequency of 2 Hz means "It happens at 2 per second."

The time it takes for the thing to happen once is exactly the

'reciprocal' of the frequency ... ' 1 ' divided by the frequency.

If the frequency is 2 Hz, then the thing happens every 1/2 second.

If the frequency is 74 Hz, then it happens every 1/74 of a second.

If the frequency is 1 KiloHz, then it happens every 1/1000 second.