Why does no refraction occur when the media have the same index of refraction?

What color of light must blue light mix with to create white light? a. yellow b. white c. blue d. green

For which pair of objects would adding the same a

Which body is in equilibrium? (1) a satellite orbiting earth in a circular orbit (2) a ball falling freely toward the surface of earth (3) a car moving with a constant speed along a straight, level road (4) a projectile at the highest point in its trajectory