You wanted to design a doorbell system that was able to differentiate between the front door and the back door with a different sound, but the entire system was housed in the same unit. How would your design have to change in order to make that possible? Describe your new unit OR draw a detailed picture including labels for your new doorbell.

Atwo-stage air compressor operates at steady state, compression 10m^3/min of air from 100 kpa and 300k to 1200 kpa. an intercooler between the two stages cools the air to 300k at a constant pressure of 350 kpa. the compression processes are isentropic. a) calculate the power required to run the compressor, in kw b) compare the result to the power required for isentropic compression from the same inlet state to the same final pressure.

Explain why electric current cannot exist if a current doesn't have a voltage source.

When is a current produced? when the terminals of an electrochemical cell are connected by a wire if the electric circuit is opened in an electrochemical cell if the electrolyte is removed from an electrochemical cell when the electrodes are reversed in an electrochemical cell