Asinusoidal wave on a transmission line is specified by voltage and current in phasor form: v s ( z ) = v 0 e α z e j β z and i s ( z ) = i 0 e α z e j β z e j ϕ where v0 and i0 are both real. (a) in which direction does this wave propagate and why? (b) it is found that α = 0, z0 = 50 ω, and the wave velocity is vp = 2.5 × 108 m/s, with ω = 108 s−1. evaluate r, g, l, c, λ, and ϕ.

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w