

Hi Adarsh,
The minimum frequency of incident radiation below which the emission of electron is not possible or phototelectric effect is not possible is called threshold frequency.
For better understanding please visit our channel, and watch = https://www.youtube.com/watch?v=eplTB8PiUKc&list=PLCzaIJYXP5YdocJyVpJuUxY6QUw3GnQZt&index=6
Hope you got your answer
Thanks for asking
