As mentioned in Sec.7.5, alkali metals are transparent to ultraviolet light. Assuming that...

As mentioned in Sec.7.5, alkali metals are transparent to ultraviolet light. Assuming that the refractive index is primarily due to the free electrons and that there is one free electron per atom, calculate for Li, K and Rb; you may assume that the atomic weights of Li, K and Rb are 6.94, 39.10 and 85.48 respectively; the corresponding densities are 0.534, 0.870 and 1.532 g/cm3. Also, the values of various physical constants are: m = 9.109 × 10 – 31 kg, q = 1.602 × 10 – 19 C and ε0 = 8.854 × 10 – 12 C/N-m2.

[Ans: 1550 Å, 2884 Å and 3214 Å; the corresponding experimental

values are 1551 Å, 3150 Å and 3400 Å respectively].