Steam at a temperature TH = 205 ∘C and p = 1.00 atm enters a heat engine at an unknown flow rate. After passing through the heat engine, it is released at a temperature TC = 100 ∘C and p = 1.00 atm . The measured power output P of the engine is 300 J/s , and the exiting steam has a heat transfer rate of HC = 2400 J/s . Find the efficiency e of the engine and the molar flow rate n/t of steam through the engine. The constant pressure molar heat capacity Cp for steam is37.47 J/(mol⋅K) .

Part A:
What is the efficiency of the heat engine?
Express the efficiency numerically to three significant figures.

Calculate the work done by an external agent during an isothermal compression of 1.00 mol of oxygen from a volume of 22.4 l at 10∘c and 1.0 atm pressure to 16.8l

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.