Induction hobs are operated by a powerful electro-magnet below the hob's glass surface, which acts directly on the molecules of the ferrous material in the pan above, agitating them to the point where heat is produced. Because the rate of agitation can be directly controlled by the electrical flow to the magnet, the effect of any adjustment is immediate.
One benefit of induction heating is that it is extremely fast, powering up and switching off immediately, making it as controllable as gas. It can take as little as five seconds for water to begin to boil on an induction hob. Reducing the pan to simmering is equally quick, as there is little residual heat to slow things down.
Another benefit is that heat is distributed evenly throughout the pan, meaning you are less likely to burn the contents and there is less need to stir to spread the heat evenly. Finally, with just a smooth glass surface to wipe over, and no burnt-on spillages, induction hobs are a breeze to clean.
All copper pans and some aluminium and anodised pans are not induction safe.