Top 10 Interview questions about Analytical balance.
1. What is an analytical balance, and how does it work?
An analytical balance is a highly sensitive laboratory instrument used to measure mass with extreme precision, typically to the nearest 0.1 mg. It works by comparing the sample’s mass with known reference masses in a controlled environment to ensure accuracy, compensating for environmental factors such as air currents.
2. What are the key features of an analytical balance?
Key features include a high degree of precision, a draft shield to prevent air currents from affecting measurements, a digital readout, and the ability to measure small quantities of substances (often down to 0.1 mg or finer). Some also come with built-in temperature and humidity compensation for greater accuracy.
3. Why is calibration important for an analytical balance?
Calibration ensures that the analytical balance is accurate and gives correct readings. Regular calibration is important because over time, factors like wear and environmental conditions can affect the balance’s precision. Calibration involves using known reference weights to check and adjust the instrument’s readings.
4. How do you calibrate an analytical balance?
Calibration is done using certified reference weights. The balance is adjusted until it reads the correct weight of the standard weight. This process should be done at regular intervals and after moving or cleaning the balance to ensure continued accuracy.
5. What factors can affect the accuracy of an analytical balance?
Several factors can affect the accuracy of an analytical balance, including temperature fluctuations, humidity, air currents, vibrations, and static electricity. Proper use of the balance, such as ensuring the area is stable and free from drafts, helps minimize these effects.
6. What is the draft shield, and why is it necessary?
A draft shield is a protective enclosure surrounding the weighing pan of the analytical balance to prevent air currents from affecting the weight measurement. Since even small air currents can impact highly sensitive measurements, the draft shield ensures greater accuracy.
7. How should you handle substances when weighing on an analytical balance?
When weighing substances, it is essential to handle them carefully to avoid contamination or loss. Use tweezers, weighing boats, or paper to transfer substances, and always ensure that the container used is clean and dry. After use, clean the balance and the pan to maintain precision.
8. What is the typical range of weights that an analytical balance can measure?
Analytical balances typically have a range from 0.01 mg (0.00001 g) to several kilograms, but they are mainly used for measurements in the microgram range (0.1 mg) to ensure high precision. The exact range depends on the model and type of balance.
9. How does an analytical balance differ from a regular balance or scale?
Analytical balances are much more precise than regular balances or scales, offering measurements with greater sensitivity (to the 0.1 mg level). Regular balances are less sensitive and typically measure larger amounts of substances with less concern for minute variations in mass.
10. What safety precautions should be taken when using an analytical balance?
Key safety precautions include ensuring the balance is placed on a stable, vibration-free surface, avoiding drafts, and regularly checking for calibration. Users should also wear gloves to avoid contaminating substances with oils from their skin and should handle the balance with care to prevent accidental damage.
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