Acoin 15.0 mm in diameter is placed 15.0 cm from a spherical mirror. the coin's image is 5.0 mm in diameter and is erect. is the mirror concave or convex? what is its radius of curvature?

15 cm

Explanation:

= Diameter of the coin = 15 mm

= Diameter of the image of coin =  5 mm

= distance of the coin from mirror = 15 cm

= distance of the image of coin from mirror = ?

Using the equation

= - 5 cm

= radius of curvature

Using the mirror equation

= - 15 cm

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.