A coin is placed at the bottom of a beaker containing water (refractive index = 4/3) at a depth of 16 cm. By what height the coin appears to be raised when seen from vertically above?

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 7.0 mm. Calculate the thickness of the glass slab.

The condition required for total internal reflection to take place is:

1. light ray passes from a rarer to denser medium
2. light ray passes from a denser to rarer medium
3. angle of incidence is less than critical angle
4. none of the above

A scientist while performing an experiment desires that no incident light escapes from the top of a glass block. He varies the angle X continuously and finally manages to achieve his objective. Which of the following options describes the correct answer?

1. Option (a)
2. Option (b)
3. Option (c)
4. Option (d)