A section of a sphere has a radius of curvature of 0.72 m. If this section is painted with a reflective coating on both sides, what is the focal length of:

The value is  

Explanation:

From the question we are told that

  The radius of curvature is  

Generally the radius of curvature is mathematically represented as

Here is the focal length hence

=>    

=>    

object 2 because all the other ones are wrong

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.