Describe the difference between simply taking measurements and doing a scientific experiment. In 2-3 sentences

In a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. what should be the radius of curvature of the cornea such that the image of an object 40.0 cm from the cornea’s vertex is focused on the retina?

Aparticle moves in a circle 1.50 m in radius . through what angle in radians does it rotate if it moves through an arc length of 2.50m? what is the angle in degrees?

Does current flow through or across a resistor?