Thread: Halide Q & A
View Single Post
Unread 01/02/2009, 07:59 PM   #38
Zimster
Registered Member
 
Zimster's Avatar
 
Join Date: Aug 2008
Location: Maple Grove, MN
Posts: 86
Quote:
I've heard that if a beam of light is pointed out through the tank side, it will be contained by the glass. Is it reflected back in? or is it wasted? What effect does the black panel have?

the answer to that is both. Some is reflected and some is transmitted. The amount that gets reflected is dependent upon the angle at which the light interacts with the glass.

To have the beam of light fully reflected (total internal reflection {TIR}) the angle of light must be greater than the critical angle of glass from water. The indices of water and glass are 1.333 and 1.5 respectively. Using Snell's Law, the critical angle occurs at an angle of 62.7 degrees according to the normal (perpendicular to the glass). Any angle smaller will transmit light.

The black panel will just soak up all the transmitted light.


Zimster is offline   Reply With Quote