Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R). Assertion (A): Diamond is used for cutting glass. Reason (R): Diamond has a high refractive index. Choose the most appropriate answer:
Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Analyzing Diamond Properties: Cutting Glass and Refractive Index
This question asks us to evaluate two statements about diamond: one regarding its use for cutting glass (Assertion) and another about its refractive index (Reason). We need to determine if each statement is correct and if the Reason explains the Assertion.
Let's break down each statement:
Assertion (A): Diamond is used for cutting glass.
Analysis of Assertion (A):
- Diamond is known for being the hardest naturally occurring substance.
- Glass is a relatively hard material.
- Due to its extreme hardness, diamond is capable of scratching and cutting other hard materials, including glass.
- Tools used for cutting glass often have a small piece of diamond embedded in them.
- Therefore, the statement that diamond is used for cutting glass is correct.
Reason (R): Diamond has a high refractive index.
Analysis of Reason (R):
- Refractive index ($\mu$) is a measure of how much light bends when passing from one medium to another.
- A high refractive index means light bends significantly when entering the material.
- Diamond has a refractive index of approximately 2.42, which is indeed considered high compared to most other materials (e.g., water is about 1.33, glass is typically 1.5).
- This high refractive index, along with its high dispersion (ability to separate white light into colors), is responsible for the brilliance and sparkle of a cut diamond gemstone.
- Therefore, the statement that diamond has a high refractive index is correct.
Evaluating the Relationship between Assertion (A) and Reason (R):
Now, we need to consider if Reason (R) is the correct explanation for Assertion (A).
- Assertion (A) states that diamond is used for cutting glass because of its ability to physically break or cut the glass material. This capability is directly related to the hardness of diamond.
- Reason (R) talks about the refractive index of diamond. The refractive index is an optical property that describes how light interacts with the material (bending and slowing down). It affects the appearance of the diamond (its sparkle and brilliance).
- The optical property (refractive index) has no bearing on the mechanical property (hardness) that allows diamond to cut glass.
- Diamond cuts glass because it is much harder than glass, not because it has a high refractive index.
So, while both statements are correct, the high refractive index of diamond is not the reason why it is used for cutting glass. The reason is its exceptional hardness.
Based on this analysis:
- Assertion (A) is correct.
- Reason (R) is correct.
- Reason (R) is NOT the correct explanation for Assertion (A).
Let's look at the given options:
- Option 1: (A) is correct but (R) is not correct - Incorrect, (R) is correct.
- Option 2: (A) is not correct but (R) is correct - Incorrect, (A) is correct.
- Option 3: Both (A) and (R) are correct and (R) is the correct explanation of (A) - Incorrect, (R) is not the correct explanation of (A).
- Option 4: Both (A) and (R) are correct but (R) is not the correct explanation of (A) - Correct.
Therefore, the most appropriate answer is that both Assertion (A) and Reason (R) are correct, but Reason (R) is not the correct explanation of Assertion (A).
Revision Table: Diamond Properties
| Property | Description | Relevance to Cutting Glass | Relevance to Optical Properties |
|---|---|---|---|
| Hardness (Mohs Scale) | Resistance to scratching; Diamond is 10 | High hardness is the primary reason for cutting glass. | Not directly related to optical properties. |
| Refractive Index ($\mu$) | Measure of how much light bends ($\mu \approx 2.42$) | Not related to the ability to cut glass. | High refractive index contributes to brilliance and sparkle. |
| Crystal Structure | Cubic lattice of carbon atoms | Contributes to extreme hardness and density. | Affects how light travels through the material. |
| Density | Mass per unit volume ($\approx 3.5$ g/cm$^3$) | Influences the material's strength and durability. | Not directly related to optical properties. |
Additional Information on Diamond Properties and Uses
Diamond is an allotrope of carbon, meaning it is one of the forms in which carbon atoms can exist in solid state. Its atoms are arranged in a crystal structure called diamond cubic. This structure gives diamond its unique properties.
- Hardness: Diamond is the hardest known natural material. Its hardness is measured as 10 on the Mohs scale. This extreme hardness makes it ideal for industrial applications like cutting, grinding, drilling, and polishing tools. When cutting glass, the sharp edge of the diamond creates a score line, which weakens the glass, allowing it to be broken along that line.
- Refractive Index: The refractive index ($\mu$) of diamond is about 2.42. This value is high compared to many other transparent materials. When light enters diamond, it slows down and bends significantly. This bending of light, combined with internal reflections within a cut diamond, is what produces its famous sparkle or 'fire'.
- Optical Properties vs. Mechanical Properties: It's important to distinguish between optical properties (like refractive index, dispersion, transparency) which govern how light interacts with a material, and mechanical properties (like hardness, strength, toughness) which govern how a material responds to physical forces. The use of diamond for cutting is a mechanical application based on its hardness, while its use as a gemstone relies heavily on its optical properties like high refractive index and dispersion.
In summary, diamond's ability to cut glass is due to its superior hardness, not its optical property of having a high refractive index.
Important Questions from Assertion and Reason
Given below are two statements:
Statement I: Arithmetic Progression is a sequence in which the addition of any two consecutive terms is a constant.
Statement II: In a Geometric Progression, the ratio of any term to its preceding term is a constant.
In the light of the above statements, choose the most appropriate answer from the options given below.
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The filament in an electric bulb does not burn up although its temperature is about 2700°C when it glows.
Reason (R): Bulb filament is made of tungsten.
In the light of the above statements, choose the most appropriate answer from the options given below.
Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R)
Assertion (A): Copper is used to make electrical wires.
Reason (R): Copper has very low electrical resistance.
In the light of the above statements, choose the correct answer from the options given below.
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Earth is the only planet known to have life.
Reason (R): Earth has an atmosphere which is a mixture of Oxygen, Nitrogen and Carbon dioxide.In the light of the above statements, choose the most appropriate answer from the options given below:
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Mercury is the second farthest planet from the Sun.
Reason (R): Mercury is the smallest planet in the entire solar system.
In the light of the above statements, choose the most appropriate answer from the options given below:
