4.72 a full-wave bridge-rectifier circuit with a 1-k load operates from a 120-v (rms) 60-hz household supply through a 12-to-1 step-down transformer having a single secondary winding. it uses four diodes, each of which can be modeled to have a 0.7-v drop for any current. what is the peak value of the rectified voltage across the load? for what fraction of a cycle does each diode conduct? what is the average voltage across the load? what is the average current through the load? d 4.73 i

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?