Calculate the most probable speed of a molecule of hydrogen at N.T.P. The Boltzmann constant is `1.38 xx 10^-23` J per degree and Avogadro's number is `6 xx 10^26` per kg mole.

Fill in the blanks: The value of Boltzmann's constant is 1.38 xx 10^-23 …………

Calculate the number of moles in : 12.044 xx10^23

Calculate the de-Broglie waveelngth of an electron of energy 400 eV.Given,lanck's constant = 6.6 xx 10^(-34) J s, mass of electron = 9.1 xx 10^(31) kg,1 eV = 1.6 xx 10^(-19) J .

Find de-Broglie wavelength of neutron at 127 ^@C .Given,Boltzmann's constant k=1.38 xx 10^(-23) J mol^(-1) k^(-1) ,h = 6.625 xx 10^(-34) Js and mass of neutron = 1.66 xx 10^-27 kg .

Calculate the radius of the third orbit of the electron in hydrogen atom.Given that Planck's constant, h=6.62 xx 10^(-34) J s,m=9.1 xx 10^(-31) kg,e=1=1.6 xx 10^(-19)C .

Calculate the De-Brogile wavelength of an electron and proton if their 10^5 m//s given mass of electron is 9.1 xx 10^(-31) kg (kilogram). Mass of proton 1.67 xx 10^(-27) kg . Plank.s constant h=6.625 xx 10^(-34) JS (Joule Second).

Each atom of an iron bar (5cmxx 1cm xx 1cm) has a magnetic moment 1.8xx10^(-23)Am^2. What will be the torque required to place this magnetised bar perpendicular to magnetic field of 15000 gauss? Density of iron = 7.8xx10^3kg//m^3, Atomic wt. of iron =56, Avogadro's number = 6.023xx10^(23)//gm mole.