In the investigation shown, students tested to see how long it takes the two metal bars to heat up enough to cause the beads of wax to fall off. One student believes
the wax on the lead rod will fall off; his lab partner says the opposite. Assuming that
aluminum has a lower specific heat than lead, which students is most likely correct and why?

A. The pieces of wax on the aluminum rose will off first because of aluminums low specific heat
B. The pieces of wax on lead rod will off first because of leads high specific heat
C. All four pieces of wax will off at the same time because metals are good conductors of head
D. The metals will not heat up enough to cause the wax to fall off because they are dense

Conventional hot-water heaters consist of a tank of water maintained at a fixed temperature. the hot water is to be used when needed. the drawback is that energy is wasted because the tank loses heat when it is not in use, and you can run out of hot water if you use too much. some utility companies are encouraging the use of on-demand water heaters (also known as flash heaters), which consist of heating units to heat the water as you use it. no water tank is involved, so no heat is wasted. a typical household shower flow rate is 2.50 gal/min (9.46 l/min ) with the tap water being heated from 51.0 ˚f (10.6 ˚c) to 120 ˚f (48.9 ˚c) by the on-demand heater.what rate of heat input (either electrical of from gas) is required to operate such a unit, assuming that all the heat goes into the water?