21 August 2022, Sunday, 8 – 10 am.

1. Draw the phase diagram of water (H$_2$O). Explain the triple point and critical point and the melting, boiling and sublimation lines. Identify the solid, liquid and vapor regions in the diagram and explain the three regions. What happens when the three lines are crossed?

2. Derive an expression for the work done by an isothermal process? If the volume of a 1-mol gas increases by a factor of 3 due to an isothermal process at 300 K, what is the work?

3. Draw the schematic diagram of a heat engine and explain its working procedure briefly? Draw the schematic diagram of a refrigerator and explain its working procedure briefly. Draw the diagram of a perfect engine and perfect refrigerator and explain why it is impossible to create them in reality?

4. A transverse wave on a taut string is modeled with the wave function $y(x,t) = 0.5 \sin(14x-7.0t)$. What is the velocity and acceleration function of this wave? [use calculus] Find the amplitude, wavelength, period and speed of the wave.

5. What is the speed of sound at 300 K? Calculate the sound intensity level in decibels for a sound wave traveling in air at 300 K and having a pressure amplitude of 0.23 Pa. Density of air at standard temperature and pressure is 1.29 kg/m.