EMF - electromotive force? I think you might have your acronyms mixed up xD Electromotive force is just the force exerted on a wire that's moving through an electromagnetic field. Do you mean electromagnetic radiation (microwaves, radio waves, x-rays, etc)? If so, well, from a laptop... absolutely minimal. If you think you need a large number of repeated exposures to x-rays from an x-ray machine, the like they use in hospitals, to have a small chance of getting, I dunno, skin cancer, then the amount of radiation from household appliances (microwave excluded, that's slightly different) is tiny and you shouldn't worry about it in the slightest. If you go staring at active microwaves for hours at a time, for days or weeks, then yeah, chances are a bit higher, but microwaves are still relatively harmless. Less so than visible light, say, and we don't worry about the dangerous effects of visible light.