Closely following a person into a secure area and thereby circumventing its physical security system.
In cooling, the amount of heat involved in melting one ton of ice in a day. Data Center air handler capacity is typically rated in tons. One cooling ton equals 12,000 BTUs.
An optical phenomenon in which light attempting to pass from one medium to another at a given angle is reflected back toward the center rather than continuing through the boundary.
Total internal reflection is what enables light to continue traveling down a long, curving fiber optic cable.