What is rectification? and what is Full wave and half wave rectification?

AC electricity is supplied by the mains supply. DC electricity is supplied by batteries and solar cells. Many devices need a DC supply rather than an AC supply. A rectifier changes AC into DC. The process is called rectification and it uses diodes.

Half-wave rectification;
A single diode can produce half-wave rectification. One half of the AC wave is removed because it cannot pass through the diode.

You should remember that one diode can produce half-wave rectification, and you should be able to recognize half-wave rectification from a voltage-time graph.

Full-wave rectification;
Half-wave rectification is achieved using one diode, but full-wave rectification needs four diodes in a bridge circuit.

Note that in full-wave rectification current passes all the time, rather than just every half cycle.