The inner and outer surfaces of a 25-cm-thick wall in summer are at 27 °c and 44 °c, respectively. the outer surface of the wall exchanges heat by radiation with surrounding surfaces at 40 °c, and convection with ambient air also at 40 °c with a convection heat transfer coefficient of 8 w/m2°c. solar radiation is incident on the surface at a rate of 150 w/m2. if both the emissivity and the solar absorptivity of the outer surface are 0.8, determine the effective thermal conductivity of the wall

Athin plate moves between two parallel, horizontal, stationary flat surfaces at a constant velocity of v = 7.5 m/s. the two stationary surfaces are spaced 4 cm apart, and the medium between them is filled with oil whose viscosity is 0.9 n·s/m2. the part of the plate immersed in oil at any given time is 2 m long and 0.5 m wide. if the plate moves through the mid-plane between the surfaces, determine the force required to maintain this motion. what would your response be if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top surface (h1)? if the plate moves through the mid-plane between the surfaces, the force required to maintain the motion will be n. if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top (h1) surface, the force required to maintain the motion would be n.

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

Select all the correct answers. which three statements about electromagnetic radiation are true?