Why does absorbance happen? What are some real-life applications of absorbance and transmittance?

Are people really 'supposed to' believe certain things..?! It can differ considerably from place to place, from time to time period..!?

One does not wish to merely 'believe' whatever, other people's opinions, other groups' doctrines or dogmas, which are pushed in your face as 'true', 'important', 'essential'.. We Have all been thoroughly Indoctrinated [and controlled!] by those others, who 'know what's best for us..!!' Some people, at least, wish to be apprised of Reality, and forget all the nonsense that is promoted as 'the Truth'..?! which is hardly 'true' at all..!! Those whose minds and emotions [and actions, activities] have been captured by unreal belief systems, often can not deviate from the dogma and dictates of 'their' peculiar group, so can not enjoy open and free discussion or interaction about 'that which really Is', 'that which may possibly Be'..!! True Freedom of Mind is a Wonderful Thing..!! ((-:: PIE in the Sky 0201.. ((-::

It cost the deaths of 50 million people in WW2 to give you your freedom. If those 50 million people had not given their lives and the Nazi's had prevailed you certainly wouldn't be asking this question on an internet forum.

I suggest you take time out and read your history, you might then just appreciate the freedom that you do have today in the 21st century. This is a constructive answer please learn from it because this is what Yahoo forums are all about.