Final answer:
The apparent thickness of the flint glass plate as viewed from above the water in an aquarium tank is calculated by summing the apparent thickness of the water layer and the glass plate itself, resulting in a total apparent thickness of approximately 12.64 cm.
Step-by-step explanation:
The apparent thickness of a flint glass plate at the bottom of an aquarium tank as viewed from above the water can be calculated using the concept of refraction. Since light bends when it moves from one medium to another, objects appear closer to the surface when viewed through water. This effect is described by the equation apparent depth = (real depth) x (n1/n2), where n1 is the refractive index of the medium in which the observer is located (air, in this case), and n2 is the refractive index of the medium containing the object (water or glass).
For the water layer:
Apparent depth = (real depth of 11.6 cm) x (n air / n water) = 11.6 cm x (1.00 / 1.33) ≈ 8.72 cm.
For the glass plate:
Apparent thickness = (real thickness of 6.50 cm) x (n air / n flint glass) = 6.5 cm x (1.00 / 1.66) ≈ 3.92 cm.
The total apparent thickness as seen from above is the sum of the apparent depths of the water and the glass plate:
Total apparent thickness = 8.72 cm + 3.92 cm ≈ 12.64 cm.