# thermodynamics heat

1. ### Hole in an aluminium plate and that plate is heated

the radius of the hole should decrease from my perspective but the book says that the radius of the hole will increase. I am not able to understand why??
2. ### Questions about the Point Function (Thermodynamics)

We know from first law of thermodynamics for a closed system that $dE$=$\delta Q$ -$\delta W$ , my question is that for a closed adiabatic system net heat transfer =0 this mean net change in energy = work done , does that mean for an adiabatic system work done is a point function as...
3. ### There is a thermodynamics problem I cannot solve

1. Consider a balloon which has thick rigid walls and from which all the air has been pumped out. Now, the valve of the balloon is slightly opened, and the balloon is slowly filled with the air from outside. Find the temperature of the air inside the balloon once the air flow has stopped (since...
4. ### I Confusion about relation of entropy with temperature.

Why can sometimes entropy remain constant with increase of temperature and vice versa?Entropy implies transfer of heat and heat must increase with temperature.I am unable to intuitively understand.
5. ### First law of thermodynamics: why some equations can't be used

1. Homework Statement A cylinder fitted with a frictionless piston contains 5.0×10-4m3 of an ideal gas at a pressure of 1.0×105 Pa and temperature of 300K. The gas is then (i) heated at constant pressure to 450K, and then (ii) cooled at constant volume to the original temperature of 300K. The...
6. ### Thermodynamic properties - Isochronic process - First law

1. Homework Statement An amount of water substance having a mass of 1 kg is contained in a vessel at a pressure of 1 MPa. It is heated for some time after which the pressure is 3 MPa. The volume of the vessel is 0.1 m3. Assuming no work is done by or to the substance, calculate the final...
7. ### When is ΔH=ΔU

In thermodynamics when can we say that ΔH = ΔU?
8. ### Why temparature only depends on internal energy, not on porv (pressure or volume)

Why temparature is only dependent on internal energy of something, say an ideal gas.
9. ### Thermodynamics adiabatic diffuser question

An adiabatic diffuser is employed to decrease the velocity of an airstream from 220 to 30 m/s. The air enters the diffuser at a rate of 8 kg/s with a temperature of 300c and a pressure of 100kpa. Determine the exit area of the diffuser if the exit pressure is 125kpa. Answer is 0.37 m^2 Guys...