A current of 77 mA in a conducting wire of an unknown material is carried by free electrons. The cross-sectional area of the conductor is 1.5×10*-6 m2.Find the density of free electrons in the material if the average speed of the free electrons along the wire is 0.18 mm/s. Use a value of 1.6×10*-19 C for the electron charge.

The amount of heat required to change liquid water to vapor at its boiling temperature is 2256 kj/kg. the amount of heat required to change liquid mercury to its vapor state at its boiling temperature is 295 kj/kg. one kg of each substance is currently at its boiling point. how will the amount of thermal energy required to change each substance from a liquid to a gas differ?