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Entropy

Entropy(S) is a thermodynamic state function that measures the degree of energy dispersal or randomness/disorder of a system. Unit:- J K-¹ For Specific entropy  Unit :- J Kg K-¹   ●                         dS=dQ/T For reversible process ds=0 For irreversible process ds>0 Examples :- ●Ice melting → entropy increases. ●Water evaporating → entropy increases. ●Gas expanding freely → entropy increases. ●Heat naturally flowing from hot to cold → total entropy increases.

Electromagnetic induction.

Electromagnetic induction is the phenomenon of production of an induced emf (electromotive force) in a closed circuit whenever the magnetic flux linked with the circuit changes. The induced emf is given by e=-dΦ/dt For a coil of N-turns e=-NdΦ/dt where magnetic flux is Φ=BAcosθ Lenz's law:- The induced current always flows in such a direction that it opposes the change in magnetic flux that produces it.

What is resonance?

Resonance is the phenomenon in which a system oscillates with maximum amplitude when the frequency of the external periodic force equals its natural frequency.

What is a wavefunction?

A wave function (ψ) is a mathematical function that describes the quantum state of a particle. Its squared magnitude gives the probability density of finding the particle at a particular position. |ψ|² = Probability density In short : The wave function tells us what we can know about a quantum particle and where it is likely to be found.

Quantum Tunneling.

Quantum tunneling is a phenomenon where a quantum particle can pass through a potential barrier even when its energy is less than the barrier height. In classical physics: ❌ Impossible In quantum physics: ✅ Possible Example : It is responsible for α-decay and is used in scanning tunneling microscopes (STM).

What is Doppler effect ?

The Doppler effect is the apparent change in frequency of a wave when there is relative motion between the source and the observer. ●Source approaching → frequency increases → higher pitch ●Source moving away → frequency decreases → lower pitch Example :-The pitch of an ambulance siren sounds higher as it approaches you and lower as it moves away.

What is chemical potential ?

Chemical potential is the change in the Gibbs free energy of a system when one mole of a substance is added at constant temperature and pressure.                     μ=(∂G/∂n)ₜ,ₚ where G is Gibbs free energy and n is the number of moles. ● Chemical potential represents the driving.     force for the movement of particles. ☆  Particles naturally move from higher.             chemical potential to lower  chemical potential. ☆  At equilibrium, the chemical potential is.       the  same throughout the system.