Practice Problems

1. A 2 kg block of metal at 100°C is dropped into 500 g of water at 25°C. Find the final equilibrium temperature. (Specific heats: metal 400 J/kg·K, water 4186 J/kg·K)
2. A gas in a cylinder absorbs 600 J of heat and performs 250 J of work. Calculate the change in internal energy.
3. Determine the efficiency of a Carnot engine operating between 700 K and 400 K.
4. Explain why entropy always increases in a spontaneous process.
5. A refrigerator removes 300 J of heat from the cold compartment while consuming 100 J of work. Calculate the COP.
6. Calculate the wavelength of a particle of mass 2 × 10^-26 kg moving at 1 × 10^3 m/s. (Optional: relate to quantum concepts.)
7. Describe the energy flow in a heat engine using a simple diagram.
8. Explain how the first law of thermodynamics is applied in calorimetry experiments.