Solution:
According to the question, refractive index of the water (μw) is 4 / 3 and the real depth of coin is 12 cm
We have to find the shift in the image
Expression for the shift in image in terms of refractive index is given below –
Shift = Real depth × (1 – 1 / μ)
Putting values, Shift = 12 × (1 – 3 / 4)
Shift = 12 / 4
Therefore, Shift = 3 cm