Which of the following statements about solid state diffusion is incorrect a)- for a given material at a given temperature, surface diftusivity is typically larger than the volume (bulk) diffusivity. b)-diffusion is faster at elevated temperatures c)- diffusion flux is proportional to the concentration gradient. d)-diffusivity is a temperature-independent property of a given material.

Asteel wire of 2 mm diameter is fixed between two points located 2 m apart. the tensile force in the wire is 250n, if its density of steel is given by 7830 kg/m3 the fundamental frequency of vibration hz? ?

The load on a bolt consists of an axial pull of 10 kn together with a transverse shear force of 5 kn. the bolt material has a yield strength of syt syc 100 mpa. find the diameter of the bolt at factor of safety n-0.5, n 1 and n-2 using maximum shear stress theory

An array of m-50 thermoelectric modules is installed on the exhaust of a sports car. each module has an effective seebeck coefficient of sp of 0.143 5vk and an internal electrical resistance of r.-4 ? in addition, : (15 points each module is of width w 60mm and contains n=100 pairs of semiconducting pellets. each pellet hasan overall length of 2l-5mm and a cross-sectional area as 1.2 x 10'm and is characterized by a thermal conductivity of kpl2w rnk. the hot side of each module is exposed to exhaust gases at·p650c with hia4ow rrk while the osite side of each module is cooled by pressurized water at surface) and 156 °c (at the cool surface). 11s c with h: -500w/m'k. the modules are wired n series and the load resistance is r d=400ohm .the module surface temperatures, t, and ts are 183 "c (at the hot surface and 156c (at the cool surface) a)-draw a schematic of this scenario and label all parts. a. b. if the induced current, i, is 0.15 amps, what is the total power (pa) for one module? c. what is the total power harvest from the exhaust with all 50 modules?