If a body vibrates 50 times in a second, then its frequency is ______

If a body vibrates 20 times in a second, then its frequency is 20 Hz.

If a vibrating body produces 20 vibrations in 10 second, then its frequency is ________ Hz.

If the time period of a simple pendulam is 10 seconds, then its frequency ius ______Hz.

An object oscillates 50 times in one second. What should be its frequency ?

When the current changes the direction 50 times in one second then the frequency of a.c. is 50 Hz. is this statement true.