GEOLOGY
PHYSICAL MINERALOGY
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
the critical angle effect
|
|
|
the selective absorption
|
|
|
Either A or B
|
|
|
None of the above
|
Detailed explanation-1: -So it works on principle of double refraction.
Detailed explanation-2: -The critical angle for the type of glass used to make the prism = 42 o. The ray of light is turned through 90 o. At A the ray of light is incident along the normal and passes straight through into the glass prism without being bent.
Detailed explanation-3: -A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68° between one vertical side and the end surface. The prism is cut diagonally in half, the cut being made at right angles to the shorter diagonal of the end face.
Detailed explanation-4: -A Nicol prism is made up of two prisms of calcite (CaCO3) cemented with Canada balsam. We know that polarization is a process by which the vibrations of a transverse wave are confined to one geometric orientation (direction). A Nicol prism is a polarizer that is used to produce and analyse plane polarized light.