How much faster, in meters per second, does light travel in a crystal with refraction index 1.84 than in another with refraction index 2.32?
a) 3.99 x 10⁸ m/s
b) 2.17 x 10⁸ m/s
c) 1.08 x 10⁸ m/s
d) 5.43 x 10⁸ m/s