Quartz Properties and Spectral Absorption
Quartz is a widely recognized mineral composed essentially of silicon dioxide (SiO₂). Its basic structural unit is the [SiO₄]⁴⁻ tetrahedron, where four oxygen atoms surround a central silicon atom. These tetrahedra link together to form a crystal lattice.
The interaction of Quartz with the electromagnetic spectrum determines its optical properties, including how it absorbs or transmits different wavelengths of light and radiation. The question asks specifically about the part of the electromagnetic spectrum that Quartz absorbs.
Understanding Quartz Absorption Spectrum
Quartz interacts differently with various regions of the electromagnetic spectrum:
- Visible Spectrum: Pure Quartz is largely transparent to visible light. This means it transmits most visible wavelengths without significant absorption, which is why clear quartz crystals appear clear.
- UV Region: Quartz shows significant absorption in the ultraviolet (UV) part of the spectrum. This absorption is primarily due to electronic transitions within the material, particularly involving the Si-O bonds. The energy of UV photons is sufficient to excite electrons in the quartz structure, leading to absorption. The specific cutoff wavelength depends on the purity and structural perfection of the quartz sample but generally occurs in the UV region (often below 300 nm).
- Infrared Regions (Thermal IR and Middle IR): Quartz also interacts with infrared (IR) radiation. Absorption occurs due to the vibrational modes of the [SiO₄] tetrahedra and the crystal lattice. These absorptions are characteristic but often considered distinct from the broad electronic absorption seen in the UV region.
Conclusion on Spectral Absorption
Based on the electronic band structure and vibrational properties, Quartz exhibits distinct absorption characteristics across the electromagnetic spectrum. The most prominent absorption related to electronic transitions occurs in the UV Region. While interactions happen in the visible and IR regions, strong absorption is a key feature in the UV range.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A sphere of volume V is made of a material with lower density than water. While on Earth, it floats on water with its volume f1V (f1 < 1) submerged. On the other hand, on a spaceship accelerating with acceleration a < g (g is the acceleration due to gravity on Earth) in outer space, its submerged volume in water is f2V. Then:
A railway wagon (open at the top) of mass M1 is moving with speed v1 along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M2 and speed becomes v2. Taking the rain to be falling vertically and the water stationery inside the wagon, the relation between the two speeds v1 and v2 is :
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
One block of 2⋅0 kg mass is placed on top of another block of 3⋅0 kg mass. The coefficient of static friction between the two blocks is 0⋅2. The bottom block is pulled with a horizontal force F such that both the blocks move together without slipping. Taking acceleration due to gravity as 10 m/s2, the maximum value of the frictional force is :
