Content Preview

EGEE 101- Exam 1 2025 Questions and Answers Radiaton - ....ANSWER ...-Radiative heat transfer is how the "warmth" of the sun is transferred to you when you're out or how you warm your hands in front of the fire. Convective - ....ANSWER ...-Convection is the heat transfer due to bulk movement of molecules within fluids. -The water molecules are free to roam about as they are not fixed in relative positions (unless frozen) like the metal atoms. So as a water molecule heats up, it has more energy and travels further. The molecules moving around have lots of collisions (think bumper cars), but this "molecular billiards" occurs without energy loss, and so, imagine breaking at pool but the balls never stop; they will keep on colliding until there is a distribution of energy. This distribution will be a certain shape with a certain portion of the molecules having certain energy levels. As the water warms up, this distribution will simply shift to the right into a higher energy level (temperature). The Refrigerator : - ....ANSWER ...-The casing is simply an insulated box, so the heat cannot get in (remember that heat flows from hot to cold, so it would not be correct to say insulation keeps the cold in). At the back, there is a heat exchanger, a coil where the heat from inside the refrigerator can be dissipated—yes, this means that in the summer your refrigerator is pumping out heat which you are removing with the air conditioner (silly, isn't it!) But as heat flows from hot to cold, how did we manage to get it to flow the other way? We used a heat pump, to which we give energy so we can move heat; this is achieved because of the properties of the refrigerant and the use of the …FOR STUDENTS ONLY…©️2025 ALL RIGHTS RESERVED… 1