Please provide solutions so I can understand them better. Thank you

1. A particular heat engine does 10.000 ] of work on a gas on the compression stroke, and the gas does 60.000 joules of work on the power stroke. Which of the following PV' diagrams indicates the net work done by the heat engine in one cycle? 50,000 J 50,000 J 50,000 J -50.000 J V V (a) (b) (c) (d) 2. Two long parallel wires 2.5 meters apart are cach carrying 0.50 ampere of current, as shown. Find the magnetic field at point P due to the current in the top wire. 12 P 3. The heat of fusion of gold is 64.5 x 10' J/kg. The melting point of gold is 1063.C. If 536 grams of gold is melted. what is the change in entropy? 4. (a) Find /2 in this circuit. (b) Then find /2 if an ammeter whose T resistance is 0.750 ohm is used to measure the current /2. 12 12 30.0 V 25.0 0 3 503 5. A four-loop coil is pierced by 600 webers of flux, as shown. The flux is reduced to 200 webers in 8 seconds. Find the average value of the induced voltage. N = L