An achromatic thin prism for the ‘C’ and ‘F’ Fraunhofer lines is to be made by u

Question

An achromatic thin prism for the ‘C’ and ‘F’ Fraunhofer lines is to be made by using the crown and flint glasses described below.

f the crown glass prism has a prism angle of 15°, determine

(a) the required prism angle for the flint glass prism.

(b) the resulting “mean” deviation for the D line.

(10 points)

{Hint: The achromatic thin prism is a combination of crown and flint prisms such that the relative dispersion between the C and F lines due to the first prism is reversed by the second prism}

wave length (nm) characetrization crown glass (n) flint glass(n) 486.1 F, blue 1.5286 1.7328 589.2 D, yellow 1.5230 1.7205 656.3 C,red 1.5205 1.7076

Explanation / Answer

dR = (nR - 1)A and dB = (nB - 1)A

Dispersion () = dR - dB = (nB - nR)A

Mean deviation (dY) = (nY - 1)A

Dispersion () = (1.5286 -1.5205 ) * 15 =0.1215 degrees

Mean deviation (dY) = (nY - 1)A = 1.5230-1 * 15 = 7.845

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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