A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 15cm 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

`rArr` Height of pin which is hifted,
d = real thickness of slab - real thickness in slab
= Real thickness of `"slab" - ("real thickness of slab")/(mu)`
`t - (t)/(mu) = t [1 -(1)/(mu)]`
`= 15 (1 - (1)/(1.5)) = 15 xx (0.5)/(1.5)`
= 5 cm
Answer does.nt depend on location of slab.
`rArr` Another method :
Refractive index `mu = ("real depth")/("apparent depth")`
`therefore` Apparent depth `=("real depth")/("refractive index" mu)`
`= 15 /1.5`
`= 10 cm`
`therefore` Shift of pin = 15- 10
= 5 cm
Anwer doesn.t depend on location of slab.