An ideal otto cycle with air as the working fluid has a compression ratio of 10. the minimum and maximum temperatures in the cycle are 540 and 2400 r. accounting for the variation of specific heats with temperature, determine: (a) the amount of heat transferred to the air during the heat-addition process. (b) the thermal efficiency. (c) the thermal efficiency of a carnot cycle operating between the same temperature limits.

The heater element of a 120 v toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. the resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ω·m. the toaster is operated at a voltage of 120 v. (a) what is the power drawn by the toaster? (b) if the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) when the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to it’s resistivity when at operating temperature? explain.