Where can I buy a bulb (point source) that emits EM waves with wavelengths within 10% of the solar spectrum?

Answer 1

You can't, for two reasons. Firstly, there is no such thing as a point source of light -- you can approximate it, but the size cannot be zero. Secondly, to get that close to the solar spectrum would require a temperature within 10% of the sun's surface temperature, and at that temperature everything is a gas. (Fluorescent materials have too much of a line spectrum to be good approximations.) Your best bet is to use an incandescent lamp with a correction filter, such as is made by Rosco or Lee.

Answer 2

I am not aware of a bulb that will perform as you suggest.

An Incandescent bulb with the appropriate filter is about as close as you are likely to get.

Also, bulbs are not point sources. The size of their filament is
always much larger than a single point. I think that you can
approximate a point source, however, by using a pin hole
drilled in a sheet of dark painted metal. Light from the bulb
would be blocked in all directions except for those rays
which exited through the pin hole in the metal. For experimental
purposes, that might work for you.

Answer 3

The bulb in the source is used by photographers to simulate the color of sunlight, but it isn't a point source. And these bulbs burn out after only 3 hours use.