Calculate the dispersive power for crown glass from the given data $ \mu_v = 1.523 , \mu_r = 1.5145$:

0.1639                                                            0.01639 1.639    2.639

0.01639

$\text{Mean refractive index } \mu_{av} = \frac{\mu_v + \mu_r}{2} = 1.5187$ $ \text{Dispersive Power }\omega = \frac{\mu_v - \mu_r}{\mu -1} = 0.01639$