A small pin fixed on a table top is viewed from above from a adistance of 50 cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 15 cm thick glass slab held parallel to the table ? Refractive index of glass = 1.5. Does the answer depend on the location of the slab ?

Explanation

`mu=1.5,` real thickness = 15 cm
`mu=("Real depth")/("Apparent depth")`
`15=("1.5")/("Apparent Depth")`
`therefore" Apparent Depth "=(15)/(1.5)=10cm`
`therefore" Pin appears raised by "15-10=5cm.`
The result is independent of the location of the slab.