Can Arduino Uno R3 running 24/7 with 12v power supply

I’m afraid to use arduino uno for 24 hours with 12v power supply. Does it not cause damage ?. Im afraid because if i use arduino uno with 12v power supply, arduino start overheating. Because when I use 5v power supply. led to arduino seems dim … So my question, is arduino uno can work for 24 hours with 12v power supply??

(deleted)