Yes, an induction cooker is faster than traditional electric cooktop and gas cooker. It allows instant control of cooking energy similar to gas burners. Other cooking methods use flames or red-hot heating elements but induction heating only heats the pot.
No, an induction cooker transfers electrical energy by induction from a coil of wire when electric current flowing through it. The current creates a changing magnetic field and produces heat. The pot gets hot and heats its contents by heat conduction. The cooking surface is made of a glass-ceramic material which is a poor heat conductor, so only a little heat is lost through the bottom of the pot which incurred minimal wastage of energy when compared with open flame cooking and normal electric cooktop. The induction effect does not heat the air around the vessel, resulting in further energy efficiency.
Induction cooktops produce extremely low frequency radiation, similar to microwave radio frequency. This type of radiation diminishes to nothing at distances of a few inches to about a foot from the source. During normal use, you will not be close enough to the operating induction unit to absorb any radiation.