Estimate the fraction of electrons,which are excited from the energy gap of 1.1 eV at a temperature of 300 K. Given Boltzmann's constant,`k=1.38 xx 10^(-23) J`.

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

A doped semiconductor has impurity levels 40 MeV (millielectron volt) below the conduction band In a thermal collision,an amount of energy k T is given ot the extra electron loosely bound to the impurity ion and this electron is just able to jump into the conduction band.Calculate the temperature T. Given,Boltzmann's constant , k=8.62 xx 10^(-5) eV K^(-1) .

If the free electron density of copper is 8.6xx10^(28)m^(-3) and resistivity of copper at room temperature is 1.7xx10^(-6)Omega cm , find the relaxation time for the free electrons of copper. Given, mass of electron =9.1xx10^(-31) kg , and charge of electron =1.6xx10^(-19)C. Boltzmann's constant k = 1.38 xx 10^-23 J K^-1

Calculate the wavelength of a photon of energy 10^(10) eV (electron volt(. Given Planck.s constant h=6.625 xx 10^(-34) Js (Joule Second).

Calculate the momentum of electrons , if their wavelength is 1 overset @A . Given that Plank.s constant , h= 6.626 xx 10^(-34) Js,mass of electron, m=9.1 xx10^(-31) kg.

The total energy of an electron in the second excited state fo hydrogen atom is -1.51 eV .Calculate the potential energy of the electron in this state.

Estimate the number of free electrons in 1 g of water and the negative charge possessed by the. Given that Avogadro number = 6.02 xx 10^23 and molecular weight of water = 18

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 .