The use of ultraviolet or fl uorescent dyes in an r-1234yf system is

Leak detection.

Explanation:

Hello,

Organic compounds such as r-1234yf (2,3,3,3-Tetrafluoropropene) are being used as new generation refrigerants for automobiles or cooling systems. Nonetheless, leaking is an issue present in most of the piping systems due to possibles crashes or design issues which turn out into the break of the system so the fluid flowing though it could escape out. To overcome this issue, ultraviolet or fluorescent dyes started being used to detect such escapes as they are visible either by the human or by an electronic detector allowing its further fix.

Best regards.

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.

the answers would be

the first one and the second one