Light affects many electronic circuits. Test a reverse-biased 1N4148 diode's sensitivity to light because it has a clear glass case.
A black case is opaque and blocks light.
there are white Opto isolator chips and gray color chips from some firms
Many ceramic MIL grade chips are in gray color.
It will not be now proper to tell that immediately after seeing the heading, i thought of effect on semiconductor devices if exposed to light. and i am happy that AudioGURU has just covered this concept. Thanks AG.
That's only true if the object is absorbing radiation, when it's emiting radiation it's the other way round. If you take two resistors both disipating 1W and painted one white and the other black the white resistor will be hotter than the black resistor.
I have seen some very early (early 60's) ICs and they came with a white plastic pop-off cover. The actual IC was in a white ceramic type blob with heavy gold wires coming out. Probably only a couple of AND gates in it.
is pointing out a fact. It does not mention whether black is a color or not -- it says "Black is better...", not "The color black is better...".
Now, if you want an argument from a scientific stance -- try mixing cyan, yellow and magenta (the colors in your inkjet) and tell me what color you achieve.
Oh, and as for my opinion on why IC's are black -- I'd bet it has something to do with the "old days" when IC's were secretive. Kinda like making a black PCB to make it more difficult to reverse engineer. Making an IC black would make it almost impervious to light.
Can you think of a better colour than black? Surely not red, blue, or purple? I think it's just because black is the native colour of the plastic used without dying and therefore the cheapest.