Light comes in from air at 3x 108msec at 700nm n1100 then

Question

Solve the all parts of following problem:

Problem: Light comes in from air at 3x 10⁸m/sec at 700nm N1=1.00 then it is a new material and slows to 1.5 x 10⁸ m/sec.

Part I: What is the index of refraction of the material?

Part II: What is the wavelength of the light in the material?

Please provide clear step by step solution with notes on concepts and equations being used. Thank you.