First Law of Thermodynamics Explained
The first law of thermodynamics is a core principle governing energy transfer and transformation within physical systems.
Principle of Conservation
This law fundamentally states that energy in an isolated system remains constant over time. It cannot be created or destroyed, only changed from one form to another.
- Energy Conversion: The law highlights that energy can be converted between different forms, such as heat, work, and internal energy.
- System Energy: For any process, the change in the internal energy of a system ($\Delta U$) is equal to the heat added to the system ($Q$) minus the work done by the system ($W$). The mathematical expression is:
$\Delta U = Q - W$
Relation to Conservation Laws
The first law of thermodynamics is essentially an expression of the conservation of energy applied to thermodynamic processes.
Other conservation laws, like the conservation of mass or momentum, are fundamental but are described by different physical laws (e.g., Newton's laws for momentum, principles of mass continuity for mass). The increase in entropy relates to the second law of thermodynamics, not the first.
Important Questions from Thermodynamics
Two blocks of ice when pressed together join to form one block because
The ratio C p/C vof the specific heats at constant pressure and volume of a monoatomic ideal gas in two dimensions is
The total number of phonon modes in a solid of volume V is \(\int_{\rm{0}}^{{\rm{ω_ D}}} {{\rm{g}}\left( {\rm{ω }} \right)\,} {\rm{dω }}\) = 3N, where N is the number of primitive cells, ω Dis the Debye frequency and density of photon modes is g( ω ) = AV ω2 (with A > 0 a constant). If the density of the solid doubles in a phase transition, the Debye temperature θ D, will
The dispersion relation of a gas of non-interacting bosons in d dimensions is E(k) = ak s, where a and s are positive constants. Bose-Einstein condensation will occur for all values of
Example of thermoplastic among the following is
