Duduli

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).

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.

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.

Even though billions of stars emit light, space appears dark because most of the universe is empty.Light travels in straight lines and doesn’t illuminate empty space unless it interacts with matter. So, between stars and galaxies, there is very little material to scatter the light toward our eyes.

The polarizability of a hydrogen atom describes how easily it's electron cloud can be distorted by an external electric field.

The rank of the tensor is the number of suffixes or indices(without counting an index which appears once as a subscript) in the symbol representing tensor.