Question

Which of the following correctly states the property of tourmaline crystal?
A. Absorbs ordinary light and transmits extraordinary.
B. Absorbs extraordinary light and transmits ordinary light.
C. Absorbs both ordinary and extraordinary light.
D. Transmits both ordinary and extraordinary light.

Answer 1

Tourmaline crystal is a boron silicate mineral compound that is commonly used as a polarizer because of its property to absorb more light in one plane than the others.
Tourmaline crystal has a unique optic axis. Any electric field vector which is perpendicular to this axis will be strongly absorbed and those parallel to the optic axis will be transmitted.
The rays which have polarization in a direction perpendicular to the optical axis of the medium are called the ordinary rays. The rays which have polarization in a direction along the optical axis of the medium are called the extraordinary rays.

Complete step by step answer:
Tourmaline crystal is a boron silicate mineral compound. It is made up of elements such as aluminum, iron, magnesium, sodium, lithium, and potassium.
The process of limiting the vibrations of light rays into a particular plane is called polarization of light. The material used to polarize light is called a polarizer. The tourmaline crystal is commonly used as a polarizer because of its property to absorb more light in one plane than another. Light passing through the material becomes more and more polarized as it passes through the crystal. This type of absorption is known as dichroism. Tourmaline is the best example of a naturally occurring dichroic material.
A material is said to be dichroic when it has a different absorption for the perpendicular incident plane of light. Tourmaline crystal has a unique optic axis. Any electric field vector which is perpendicular to this axis will be strongly absorbed.
The polarized light has two components, ordinary and extraordinary. The rays which have polarization in a direction perpendicular to the optical axis of the medium are called the ordinary rays. The rays which have polarization in a direction along the optical axis of the medium are called the extraordinary rays.
The tourmaline crystal allows the rays to have polarization along the optic axis to pass through it. Therefore, it transmits extraordinary rays. The rays having polarization perpendicular to the optic axis are strongly absorbed. Hence it absorbs ordinary light.

So, the answer is option A.

Note:
A single tourmaline crystal acts as a polarizer. If we have one more tourmaline crystal then we can use it as an analyzer to analyze the transmitted light from the polarizer.