) Light enters a substance from air at 30.0° to the normal. It continues within the substance at 23.0° to the normal. What is the critical angle for this substance when it is surrounded by air?

Determine which heat transfers below are due to the process of conduction. i) you walk barefoot on the hot street and it burns your toes. ii) when you get into a car with hot black leather in the middle of the summer and your skin starts to get burned. iii) a flame heats the air inside a hot air balloon and the balloon rises. iv) a boy sits to the side of a campfire. he is 10 feet away, but still feels warm. a) i and ii b) iii and iv c) i, ii, and iv d) ii, iii, and iv