By original design, a system outputs a 10-volt pulse that is 3 seconds in duration. it is desired to upgrade the square-pulse output with a "soft-start" pulse that steps up to 10 volts in 1-volt increments spaced every 20 milliseconds. determine the signal duration t so that the "soft-start" pulse has the same signal energy as the original square pulse.

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.