A tank contains water up to a height of 30 cm and above it oil up to another 30 cm height. A shift of cm in the position of the bottom of the tank is observed when viewed from above. The refractive indices of water and oil are 1.33 and 1.28 respectively.

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(3) 14. Given: 30 cm of water (n=1.33) with 30 cm of oil (n=1.28) floating on it, viewed from above. Idea: each layer of thickness t raises everything below it by t(1-1/n), and since the shifts are all measured along the same vertical line they simply add. Water: 30(1-1/(1.33))=30× 0.248=7.44 cm Oil: 30(1-1/(1.28))=30× 0.219=6.56 cm Total shift =7.44+6.56=14 cm The oil contributes a little less than the water because it is optically the thinner of the two.

A tank contains water up to a height of 30 cm and above it oil up to another 30 cm height. A shift of ________ cm in the position of the bottom of the tank is observed when viewed from above. The refractive indices of water and oil are 1.33 and 1.28 respectively.

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