1.

A cylindrical rod of some laser material 5xx10^(-2)m long and 10^(-2)m diameter contains 2xx1025^(25) ions per m^(3). If on excitation all the ions in the upper energy level de-excite simultaneously emitting photons in the same direction, calculate the maximum energy contained in a pulse of radiation of wavelength 6.6xx10^(-7)m

Answer»

`3xx10^(-17)J`
`3xx10^(-18)J`
`3xx10^(-19)J`
`3xx10^(-20)J`

Solution :Volume of the rod `=pi r^(2)L`
`=3.14((1)/(2)xx10^(-2))^(2)xx5xx10^(-2)m^(3)`
`=3.925xx10^(-6)m^(3)`
Total number of ions, `N=2xx10^(25)xx3.925xx10^(-6)`
`=7.85xx10^(19)`
ENERGY of pulse `=(HC)/(lambda)=(6.6xx10^(-34)xx3xx10^(8))/(6.6xx10^(-7))`
`=3xx10^(-19)J`


Discussion

No Comment Found

Related InterviewSolutions