Final answer:
To find the image location and magnification caused by a concave glass surface, we apply the lensmaker's formula for refraction at a spherical surface. Using this equation along with the given refractive indices and object distance, we can solve for the image distance and magnification.
Step-by-step explanation:
To solve for the location and magnification of the image formed by a concave surface in water, we use the lensmaker's formula for refraction at a spherical surface, which is:

Where:
(refractive index of water)
(refractive index of glass)
cm (object distance, negative because object is on the same side from where the light enters)- R is the radius of curvature, which should be positive for concave surface, so
cm
Magnification (M) can be calculated using the following formula:

Solving for v gives us the image distance, which we can then use to find the magnification.