4. Suppose you are using light from a bright neon source is used to study excita

Question

4. Suppose you are using light from a bright neon source is used to study excitation of rubidium atoms To excite the rubidium atoms you need light of wavelength 405.9nm which is selected by placing a diffraction grating between the light source and the rubidium atoms. The grating ruled with 6000 lines per centimeter. a. If light from the neon source is incident normal to the grating, calculate the angle and the distance (from the central maximum) of the 3rd order intensity maximum at a distance L-3.0m from the grating (10pts).

Explanation / Answer

given wave length=405.9nm

grating lines percm is 6000

distance between two lines=width of grating(d)=1cm/6000=1.7x10pow-6m

order 3rd order formn central maximum

we know that nxlamda=dsintheta

sintheta=(3x405.9x10pow-9m)/(1.7x10pow-6m)

=0.716

theta=inversesin(0.716)

=45.7degrees

therefore aangle made by third maximum and central maximum is 45.7degrees

b)no of grating lines=3000percm

d=1cm/3000=3.3x10pow-6m

taking lamda=405.9nm

angular width theta=lamda/d

=(405.9x10pow-9)/(3.3x10pow-6)

=0.123rad

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.