About wave properties please help

If the radius of curvature of the cornea is 0.75 cm when the eye is focusing on an object 36.0 cm from the cornea vertex and the indexes of refraction are as described before, what is the distance from the cornea vertex to the retina? express your answer to two significant

Most short-period comets do not have randomly oriented orbits because

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?