Two clear but non-mixing liquids each of depth 15 cm are placed together in a glass container. The liquids have refractive indices of 1.75 and 1.33. What is the apparent depth of the combination when viewed from above? A. 19.8 cm.
B. 23.1 cm.
C. 9.9 cm.
D. None of these are correct.

A. 19.8 cm.

Explanation:

The apparent depth of the combination is

As it mentioned that the two clear but non-mixing liquid having depth of 15 cm that placed in a glass container together

Also the refractive indices would be 1.75 and 1.33

Based on the above information

As we know that

Refractive indices = real depth ÷ apparent depth

1.33 ÷ 1.75 = 15  ÷ apparent depth

So, it would be 19.736842 cm

Now the combination of apparent depth would be

= ( 19.736842 + 15) ÷ (1.75)

= 19.8 cm

hence, the correct option is A.