What is the Boltzmann constant?

What is the Boltzmann's constant? Give its value.

Why is gas constant (R) called universal gas constant? What is Boltzmann constant ?

What is Boltzmann constant. What is its value in SI units?

If k is the Boltzmann constant, the average translational kinetic energy of a gas molecules at absolute temperature T is:

The wavelength of de Broglie waves associated with a thermal neutron of mass m at absolute temperature T is given by (k is the Boltzmann constant)

"m" is the mass of a molecule, "k" is the Boltzmann constant, P is the pressure and T is the absolute temperature. The density of the gas is given by

The mean transitional kinetic energy of a perfect gas molecule at absolute temperature T is ( k is the Boltzmann constant)

The wavelength of de-Broglie wave associated with a thermal neutron of mass m kg at 27^⋅C is (KB is the Boltzmann constant and all quantities are in SI units)