Question

Which of the following properties of silica is used in making optical instruments? (1) Its hardness. (2) Red hot quartz glass does not break when plunged into water. (3) Its transparency to UV light. (4) Both 2 and 3

Short answer

Option (3): Its transparency to UV light.

Step-by-step solution

Identify Key Requirements for Optical Instruments

Optical instruments require materials that have specific optical properties, such as transparency to certain wavelengths of light. Analyze each given option to see which one fits into this requirement.

Evaluate Each Option

1. Hardness: While hardness is important for durability, it is not directly related to optical properties. 2. Resistance to thermal shock: This is a unique property but not directly useful for optical purposes. 3. Transparency to UV light: This is a crucial property for optical instruments that need to manipulate UV light.4. Both 2 and 3: Combining 3 and an irrelevant property (2) doesn't change the relevance of 3.

Determine the Most Relevant Property for Optical Instruments

Among the provided options, the property 'transparency to UV light' directly aligns with the requirements for making optical instruments. Hence, option (3) is the most relevant.

Key concepts

optical properties of silica

Silica, which is also known as silicon dioxide, has several important optical properties that make it highly desirable for use in optical instruments. One of the key properties is its ability to transmit light without significant absorption or scattering. This means that light can pass through silica with minimal loss of intensity.
Silica is known for its wide range of transparency across different wavelengths of light, from ultraviolet (UV) through visible to infrared (IR). This wide range allows it to be used in various optical applications, including lenses, prisms, and windows for lasers.
Another important optical property of silica is its low refractive index, which reduces the chances of light being deflected or bent out of its path. This property enhances the precision and effectiveness of optical instruments.

transparency to UV light

One of the most critical attributes of silica when it comes to optical instruments is its transparency to ultraviolet (UV) light. This property is particularly important for instruments that need to detect or manipulate UV light.
UV transparency means that silica can allow UV light to pass through it without being absorbed. This is crucial for devices like UV spectrometers, where it's necessary to measure the intensity of UV light accurately.
Because many other materials tend to absorb UV light, silica stands out in applications that require high UV transmission. This makes it an essential material for creating certain types of optical lenses and windows, as well as for scientific instruments and medical equipment that rely on UV light measurements.

materials for optical instruments

In the field of optical instruments, the choice of materials is critical for the design and functionality of the device. Silica is widely used due to its advantageous optical properties, including:

• High transparency across a wide range of wavelengths
• Low refractive index
• Resistance to thermal shock

These properties allow silica to be used in high-precision instruments such as microscopes, telescopes, and high-performance optical fibers.
In addition to silica, other materials commonly used in optical instruments include calcium fluoride for its UV transparency and borosilicate glass for its durability and chemical resistance.
Each material is chosen based on specific requirements, including the wavelength of light that needs to be transmitted, the environment in which the instrument will be used, and the desired durability and resilience against various physical and chemical factors.