What is the speed of light in meters per second for monochromatic light of 780 nanometers in glass with a refractive index of 1.55:

W) \(1.5\times 10^{8}\)

X) \(1.9\times 10^{8}\)

Y) \(4.65\times 10^{7}\)

Z) \(4.65\times 10^{8}\)
X) \(1.9\times 10^{8}\)