# Basic Mechanical Engineering(3110006)

BE | Semester 1  Unit : Properties of gases

## Q1 (b) Summer-2019   Derive an expression for internal energy for a closed system.

Unit : Properties of gases

## Q1 (c) Summer-2020   Derive an expression for internal energy for a closed system.

Unit : Properties of gases

## Q3 (a) Winter-2019   Prove that the difference between two specific heats of gases is equal to its characteristic gas constant.

Unit : Properties of gases

## Q3 (b) Winter-2019   Differentiate between gas constant and Universal gas constant.

Unit : Properties of gases

## Q3 (c) Winter-2019   One kg of gas at a pressure of 100 kPa and temperature of 17°C is compressed isothermally in a piston-cylinder arrangement to final pressure of 2500 kPa. The characteristic gas equation is given by the relation pV = 260 T per kg where T is in Kelvin. Find out (1) Final Volume (2) Compression Ratio (3) Change in enthalpy (4) Work done on the gas.

Unit : Properties of gases

## Q3 (a) Winter-2019   One kg gas is compressed adiabatically by following the law pV = C from initial temperature of 290 K. The initial pressure of gas is 1 bar. The initial and final volumes of gas are 0.50 ${\mathrm{m}}^{3}$ and 0.05 ${\mathrm{m}}^{3}$ respectively. Find the final temperature and pressure of gas. Assume γ =1.4.

Unit : Properties of gases

## Q3 (c) Winter-2019   Find the internal energy of 1 kg of steam at a pressure of 15 bar when steam is (1) Super-heated at a temperature of 400°C and (2) Wet with dryness fraction of 0.9. Take specific heat of superheated steam as 2.1 kJ/kg-K.

Unit : Properties of gases