Virtual Labs

Sample preparation for testing in optical microscope using VR

Which abrasive material is typically used on grinding papers or belts :

a: Diamond Explanation

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b: Aluminum oxide Explanation

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c: Silicon carbide (SiC) Explanation

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d: Magnesium oxide Explanation

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Which statement regarding grit size numbers is true ?

a: A 400 grit paper is coarser than an 180 grit paper. Explanation

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b: A 180 grit paper is coarser than a 400 grit paper Explanation

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c: Grit numbers only indicate the type of abrasive material. Explanation

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d: Grit numbers are irrelevant in the grinding process. Explanation

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Why is the specimen rotated by 90 degrees when moving from one grit size of grinding paper to the next ?

a: To ensure even wear on the grinding paper Explanation

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b: To confuse the operator and test their attention to detail Explanation

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c: To see when scratches from the previous coarser grit have been completely removed Explanation

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d: To prevent the sample from overheating Explanation

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What common problem can occur if excessive heat is generated during the initial cutting or coarse grinding stages ?

a: The sample may become too difficult to handle Explanation

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b: The sample will become magnetized Explanation

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c: The sample's internal microstructure may be altered Explanation

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d: The grinding machine will break down Explanation

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What is the general rule of thumb regarding cleanliness between different stages of sample preparation (especially when changing grit sizes) ?

a: Cleanliness is not a major concern until the final step Explanation

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b: The sample should be thoroughly washed to prevent contamination from coarser grit particles Explanation

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c: Operator's hands need to be cleaned, not the sample Explanation

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d: Quick wipe with a dry cloth is sufficient Explanation

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Why is excessive pressure generally avoided during the grinding process ?

a: It makes the specimen too hot to handle Explanation

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b: It can cause excessive material removal and waste the sample Explanation

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c: It can lead to change in the microstructure Explanation

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d: It can clog the abrasive paper too quickly Explanation

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After the final fine grinding stage (e.g., 600 grit), what is the next major step in sample preparation ?

a: Etching Explanation

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b: Microscopic observation Explanation

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c: Coarse grinding again Explanation

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d: Polishing Explanation

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