If the binding energy of electrons in a metal is 250 kJ mol–1, what should be threshold frequency of the striking photons?


Correct option is


Binding energy of 1 mole of electrons = 250 kJ 

∴ Binding energy of 1 electron  



Threshold energy (hv0) = Binding energy





To which orbit the electron in the hydrogen atom will jump after absorbing 1.94× 10–18 J of energy? 


An electron in a hydrogen atom in the ground state absorbs energy equal to 1.5 time the minimum energy required to remove the electron from the hydrogen atom. Calculate the wavelength of the electron emitted.  


Find out the number of waves made by a Bohr electron in its 3rd orbit.



When a certain metal was irradiated with a light of frequency

3.2 × 1016 Hz, the photoelectrons had twice the kinetic energy as emitted when the same metal was irradiated with light of frequency 2.0 × 1016 Hz. Calculate the threshold frequency (v0) of the metal.


The wavelength of  line of Balmer series is 6500 Å. What is the wavelength of  line of Balmer series?


The atomic spectrum of hydrogen is found to contain a series of lines at wavelengths 656.46, 486.27, 434.17 and 410.29 nm. What will be the wavelength of the next line in the series?



Calculate the energy required for the process  


The ionization energy for the H-atom in the ground state is

 2.18 × 10–18 J atom–1.


A photon of wavelength 1.4 Å collides with an electron. After collision, the wavelength of the photon is found to be 2.0 Å. Calculate the energy of the scattered electron.


What is the minimum uncertainty in the position of a bullet of a mass 5g that is known to have a speed somewhere between 550,00000 and 550,00001 ms–1?



When would de Broglie wavelength of a moving electron become equal to that of a moving proton? Mass of electron =

 9.1095 × 10–31 kg and mass of proton = 1.6725 × 10–27 kg.