In LASER S stands fora.Simultaneousb.Spontaneousc.Simulated

He-Ne laser utilizesa.Optical pumpingb.Electrical discharge and atom-atom collisionc.Electrical discharge

The number of energy levels required to get a practical laser will bea.4b.2c.3

It is possible to get complete coherence in a Lasera.Falseb.Truec.Occasionally

Nitrogen in a carbon dioxide laser isa.Used as a coolantb.Not used in this laserc.Used to induce excitation of another atom

In part B of the experiment a Michelson Interferometer is used to determine the wavelength λ of the laser. An interference pattern is observed due to the light being split into two paths with slightly different lengths.A vacuum chamber (of length d) is placed in one of the paths and the air pumped out. Then as air leaks back into the chamber the number of fringes, N, that pass a certain point are counted as the interference pattern changes.The following measurements were taken:N= 64 ± 2d= (0.077 ± 0.008) mThe wavelength λ of the laser is calculated to be 650 nm (using the value of the refractive index of air n given in the lab manual). Calculate the uncertainty of the wavelength λ of the laser in nm to the nearest whole number.