A postage stamp kept below a rectangular glass slab of refractive index 1.5 when viewed from vertically above it appears to be raised by 7.0mm calculate the thickness of the glass slab

Open in App

Solution

given, refractive index = 1.5

to find, RD (as the thichness of the glass block will be equal to its real depth)

Let, RD = x

AD = x - 7 (as the distance between the bottom of the glass slab and and apparent depth is given)

we know, refractive index = RD/AD

therefore, 1.5 = x/(x - 7)

1.5x - 10.5 = x

1.5x -x = 10.5

0.5x =10.5

x = 21 mm or 2.1 cm (as 1 cm = 10mm)

Suggest Corrections

Similar questions

A postage stamp kept below a rectangular glass block of refractive index 1.5 when viewed from vertically above, it appears to be raised by 7.0 mm. Calculate the thickness of the glass slab.

A postage stamp appears raised by 7.0 mm when placed under a rectangular glass block of refractive index 1.5. The thickness of the glass block is

Q. A dot on a paper appears to be raised by

2 c m

when viewed normally through a glass slab placed on it. Calculate the thickness of the glass slab if its refractive index is

\frac{3}{2}

Q. A glass

(n_{g} = 1.5)

block of thickness

2.7 c m

is placed on a postage stamp. What would be the apparent depth of the stamp if it is viewed. Obliquely above the glass slab ?

Q. A small pin fixed on a table top is viewed from above from a distance 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?

Join BYJU'S Learning Program