When light travels from a medium with higher refractive index to a medium with lower refractive index, there is a critical angle after which all the light is reflected (so, there is no refraction).
The value of this critical angle can be derived by Snell's law, and it is equal to

where n2 is the refractive index of the second medium and n1 is the refractive index of the first medium.
In our problem, n1=1.47 and n2=1.33, so the critical angle is
It would last as long as the applied force continued, or until the accelerating object hit something.
Potential energy (PE ) = m g h
Where:
m = mass = 3800 kg
g = acceleration due gravity = 10 m/s^2
h = heigth = 110 meters
Replacing:
PE = 3800 * 10 * 110 = 4,180,000 J
Answer;
A plain
Explanation;
A contour line connects points of the same elevation. Contour lines are usually curves. Closed contours represent hills.
Contour lines can not cross since they represent different elevations. A contour interval is the difference in elevation between one contour and an adjacent contour.