Frequency is the number of cycles per second.
It is measured in hertz (Hz), but frequencies tend to be high so kilohertz (kHz) and megahertz (MHz) are often used. 1kHz = 1000Hz and 1MHz = 1000000Hz. frequency = | 1 | and | time period = | 1 |
time period | frequency |
Mains electricity in the UK has a frequency of 50Hz,
so it has a time period of 1/50 = 0.02s = 20ms.