The electrical conductivity and the electron mobility for some metal at room temperature are 5.6 × 107 (ω-m)-1 and 0.0032 m 2/v-s, respectively. (a) compute the number of free electrons per cubic meter for this metal at room temperature. n= enter your answer for part (a) in accordance to the question statement m-3(b) what is the number of free electrons per aluminium atom? assume a density of 2.7 g/cm3.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2

Different between boring and turning?