Physics Practical 3 Class 9 Important Viva Questions with Answers (Screw Gauge)

 PRACTICAL #3

To measure the thickness of a metal strip or a wire by using a screw gauge

VIVA VOCE

1. How would you ensure the screw gauge is properly calibrated before beginning the measurements?

Ans:  Calibrate the screw gauge by ensuring the zero mark aligns accurately with the reference point when no object is being measured.

2. What factors should be considered when selecting the appropriate screw gauge for measuring the thickness of a metal strip or wire?

Ans: Choose a screw gauge with an appropriate range that can accommodate the thickness of the metal strip or wire. Consider the pitch and resolution of the screw gauge as well.

3. Can you describe the procedure for measuring the thickness of a metal strip or wire using a screw gauge?

The procedure involves gently placing the metal strip or wire between the anvils of the screw gauge, carefully rotating the thimble until it makes light contact with the object, and then reading the measurement from the scale and thimble.

4. What precautions should be taken to minimize errors during the measurement process with a screw gauge?

Ans: Precautions include ensuring the strip or wire is placed perpendicular to the anvils, avoiding over-tightening, and taking measurements at consistent pressure levels.

5. Explain the significance of taking multiple readings at different points along the metal strip or wire.

Ans: Taking multiple readings helps account for any irregularities or variations in thickness along the length of the metal strip or wire, providing a more accurate average measurement.

6. How does the pitch of the screw gauge affect the precision of the measurements?

Ans: The pitch of the screw gauge determines the distance traveled by the spindle for each complete rotation of the thimble, thereby affecting the precision of the measurements.

7. What are the sources of potential error in this experiment, and how can they be minimized?

Ans: Potential errors may arise from parallax, improper alignment, or irregularities in the surface of the metal strip or wire. Minimize errors by careful handling, alignment, and averaging multiple readings.

8. Could you explain the difference between the zero error and least count of a screw gauge, and how they are accounted for in measurements?

Ans: Zero error refers to any deviation from the true zero mark, while the least count is the smallest measurement that can be read directly from the scale. Adjust measurements accordingly to account for zero error and consider the least count for precision.

9. How would you handle situations where the metal strip or wire is not perfectly flat or uniform?

Ans: Handle non-flat or non-uniform objects by taking measurements at various points along the length and averaging the results, or by using alternative measurement methods if necessary.

10. What steps would you take to validate the accuracy of your measurements and ensure the reliability of your results?

Ans: Validate accuracy by cross-checking measurements with a standard reference, repeating measurements for consistency, and ensuring the screw gauge is properly calibrated and used according to standard procedures.