Question

A $2\text{cm}$ diameter coin rests flat on the bottom of a bowl in which the water is $20\text{cm}$ deep (${\mu }_w=4/3$). If the coin is viewed directly from above, what is its apparent diameter?

• A. $2\text{cm}$
• B. $1.5\text{cm}$
• C. $2.67\text{cm}$
• D. $1.67\text{cm}$

Answer 1

The correct option is A $2\text{cm}$

For a plane refracting surface, the lateral magnification is $1$. Thus, the image of the coin will be of the same size as the coin itself.