6) The electron volt (eV) is a convenient unit of energy for expressing atomic-scale energies. It is the amount of energy that an electron gains when subjected to a potential of 1 volt; 1 eV = 1.602 × 10–19 J. Using the Bohr model, determine the energy, in electron volts, of the photon produced when an electron in a hydrogen atom moves from the orbit with n = 5 to the orbit with n = 2. Show your calculations.

The energy of the photon is  

Explanation:

From the question we are told that  

      The first orbit is

       The second orbit is

According to  Bohr model

     The energy of difference of the electron as it moves from on orbital to another is mathematically represented as

  Where k is a constant which has a value of

       So

Now we are told from the question that

so      x eV  =  

  Therefore

see earlier answer

3. dark matter

empty space could also be a simple vacuum