What fraction (n/N) of the lattice sites are vacant at 298 K for a crystal in which the energy required to make a defect is 1 eV.`(1 eV = 1.602 xx 10^(-19) J)`

An electron is accelerated in between two plates maintained at 1000 V . What is the energy in eV acquired by the electrons? (e=1.6 xx10^(-19) C)

Calculate the wavelength and energy of radiation for the elctronic transition form infinity to ground state for one H-atom . Given e_1 =- 13. 6 eV ( 1 1 eV = 1,. 6 xx 10^(-19) J) .

Calculate the velocity of electron ejected from a platium surface when radiation of 200 nm falls on it .The work function of platinum is 5 eV(1 eV = 1.6 xx 10^(-19) J)

The mole fraction of Schottky defect and Frenkel defects, in NaCl crystal at 1000K are respectively. If energy required to produce these defects are 2eV and 3eV respectively. (1eV=1.6xx10^(-19)J and k=1.38xx10^(-23)JK^(-1))

The number of Schottky defects (n) present in an ionic compound containing N ions at temperature T is given by n = Ne^(-E//2KT) , where E is the energy required to create n Schottky defects and K is the Boltzmann constant, If the mole fraction of Schottky defect in NaCl crystal at 2900 K is X , then calculate -ln(x) , Given: DeltaH of Schottky defect = 2 eV and K = 1.38 xx 10^(-23) J K^(-1) 1 eV = 1.608 xx 10^(-19) J