Question

1.A particular material has a workfunction of (15.2 + A)/10 eV. Find the maximum wavelength of electromagnetic radiation that will result in the emission of photoelectrons from this surface. Give your answer in nanometers (nm) and with 3 significant figures. A: 19

2.Imagine the energy levels in an atom are given by E_n = - (8.30+A)eV/n². Find the wavelength of the photon emitted when an electron goes from n = (2+B) to n = 1. Give your answer in nanometers (nm) and with 3 significant figures. A:4 B:5

3. In the Bohr model for hydrogen, the energy levels are given by E_n = (-13.6eV) / n². Find the energy of a photon emitted when an electron in a hydrogen atom jumps from n = (A+3) to n = 2.

Calculate the answer in eV and make sure to include the unit. Report your final answer with three significant figures. A: 5

4. In an atom, an electron is jumping from state with an energy of –(2.45+(A/100)) eV to a state with an energy of –(5.24+(B/100)) eV. Find the wavelength of the emitted photon.

Give your answer in nm and make sure to include the unit. Report your final answer with three significant figures. A:54 B:11

Answer 1

(1) Work function of the material ( ) = ,

Also given, A= 19,

Work function of the material ( ) = = =

So, the minimum frequency required for emission i.e., thresold frequency ( ),

, where h is the planck constant

The maximum wavelength ( ) of the photoelectrons,

, where c is the speed of light

  

  .

(2) Given, Energy levels ( ) = ,

For n=1, ,

For n=2+B, ,

putting value of A=4 and B=5,

The change in energy for the transition,

  

The frequency for the transition,

  

Wavelength for the transition,

(3) Given, Energy levels ( ) = ,

For n=1, ,

For n=A+3, ,

putting value of A=5,

The change in energy for the transition,

  

(4) Given, Initial Energy level ( ) = ,

Final Energy level ( ) = ,

putting values of A=54 and B=11,

The change in energy for the transition,

  

The frequency for the transition,

  

Wavelength for the transition,