Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom, Calculate the ionisation energy of sodium is `KJ mol ^(-1).`

Energy of an electron in the ground state of the hydrogen atom is -2.18xx10^(-18)J . Calculate the ionization enthalpy of atomic hydrogen in terms of J mol^(-1) .

Yellow light emitted from a sodium lamp has a wavelength of 480 nm. Calculate the wavenumber of this light.

The energy liberated in the combination of a hole-electron pair is converted into electromagnetic radiation.What is tha band gap,if the maximum wawveelngth fo th radiation emitted is 820 nm?Gien that 1 eV=1.6 xx 10^(-19) J and h=6.62 xx 10^(-34) Js .

Light from a dicharge tube containing hydrogen atoms falls on the surface of sodium.The kinetic energy of the fastest electrons emitted from sodium is 0.73 eV.The work function for sodium is 1.82 eV.find the recoil speed of the emitting atom assuming it to be at rest before the transmition.(Ionisation energy of hydrogen is 13.6 eV).

Followig table gives information on three lines observed in the emissin spectrum of hydrogen atoms. Complete the above table by calculating the photon energy for the wavelength of 486 nm.