By law of refraction we know that image position and object positions are related to each other by following relation

here we know that



now by above formula


so apparent depth of the bottom is seen by the observer as h = 3.39 cm
Answer:
Tension in the string is equal to 58.33 N ( this will be the strength of the string )
Explanation:
We have given mass m = 1.7 kg
radius of the circle r = 0.48 m
Kinetic energy is given 14 J
Kinetic energy is equal to 
So 

v = 4.05 m/sec
Centripetal force is equal to 
So tension in the string will be equal to 58.33 N ( this will be the strength of the string )
A, 40 degrees. Reflexion laws state that both incidence and reflection angles are the same.