Question

When the zero mark on the vernier scale lies towards the right side of the zero mark of the main scale, when the jaws are in contact, then what will be the zero error? (A) zero correction in positive (B) zero correction is negative (C) zero error in positive (D) zero error does not exist

Short answer

The correct answer is (B) zero correction is negative. This is because the zero mark on the vernier scale is towards the right side of the zero mark on the main scale, indicating a positive zero error. In this case, the zero correction value will be negative because we have to subtract the error to get the correct measurement.

Step-by-step solution

Identify the position of the zero marks on the vernier and main scales

The exercise tells us that when the jaws of the calipers are in contact, the zero mark on the vernier scale lies towards the right side of the zero mark on the main scale. In other words, the vernier scale zero is not aligned with the main scale zero.

Understand the concept of zero error

Zero error occurs when the measuring instrument (in this case, the vernier calipers) does not read exactly zero when it is supposed to (i.e., when the jaws are in contact). This error is due to the misalignment of the zero mark on the vernier scale with the zero mark on the main scale.

Determine the type of zero error

Since the zero mark on the vernier scale is towards the right side of the zero mark on the main scale, it means that the actual reading will be larger than the measurement displayed on the vernier scale. This type of zero error is known as positive zero error.

Differentiate between zero error and zero correction

Zero error is the error that occurs due to the misalignment of the zero marks on the scales. Zero correction, on the other hand, is the value that must be added or subtracted from the measured value to obtain the correct value. In the case of positive zero error, the zero correction value will be negative because we have to subtract the error to get the correct measurement. In conclusion, based on the given information and our analysis: - (A) Zero correction in positive: is incorrect, because the zero correction for positive zero error will be negative. - (B) Zero correction is negative: is correct, as the zero correction will be negative for positive zero error. - (C) Zero error in positive: is correct, as the misalignment of the zero marks indicates a positive zero error. - (D) Zero error does not exist: is incorrect, because the misalignment of zero marks clearly shows that there is a zero error.

Key concepts

Positive Zero Error

Positive zero error occurs when there is a misalignment between the zero marks of the main scale and the vernier scale on the calipers. Specifically, when the zero mark of the vernier scale lies to the right of the zero mark on the main scale while the caliper jaws are fully closed. This displacement causes the calipers to display a measurement larger than the true value.

This type of error is classified as a 'positive zero error' because the reading appears greater than it actually is. It is crucial to understand this concept as it affects precise measurements in mechanical and scientific work. Without correcting this error, all recorded measurements will include an innate additional value.

• Positive zero error means the vernier scale reads higher than zero.
• Occurs due to right-sided alignment of zero marks.
• Results in incorrect added value to measurements.

Recognizing positive zero error helps one ensure greater accuracy in measurement results.

Zero Correction

Zero correction is a calculated adjustment that must be made to any reading taken with measurement instruments such as vernier calipers to eliminate the zero error, thereby ensuring an accurate measurement. In the scenario of a positive zero error, the correction is negative. This means that the miscalculated added value due to zero error needs to be subtracted from the measurement.

For instance, if the zero mark misalignment causes a positive zero error of 0.02 cm, this value should be subtracted from every measurement recorded.

• Zero correction is crucial to maintain measurement accuracy.
• For positive errors, apply a negative correction.
• Corrects the measurement value by removing innate error.

The concept of zero correction ensures that measurements reflect true dimensions, preventing errors that could affect technical or scientific outcomes.

Measurement Errors

Measurement errors are discrepancies between a measured value and the true value. Such errors can arise from various factors, including instrument misalignments, environmental conditions, or user mistakes. Measurement errors can be systematic or random.

Zero error is a type of systematic error, which consistently skews readings by a predictable amount. Positive zero error is one such example, where every reading is consistently too high unless corrected.

• Measurement errors affect data validity and reliability.
• Systematic errors like zero errors ensure predictability, aiding error correction.
• Avoiding errors improves accuracy in applications requiring precise measurements.

Understanding measurement errors is vital for anyone relying on precise measurement tools. This knowledge ensures that all measurements are as accurate and reliable as possible.

Vernier Scale Reading

The vernier scale reading involves capturing precise measurements by aligning a sliding vernier scale against a fixed main scale. When the scales perfectly align—meaning the vernier's zero lines up with the main scale's zero—measurements are accurate with no zero error.

To read a vernier scale accurately:

• Ensure no zero error by checking initial zero alignment.
• Note where the vernier scale aligns with the main scale convincingly.
• Adjust for any zero error to ensure the vernier scale provides valid results.

Accurate readings involve ensuring both scales start at zero for consistency. If a zero error exists, adjustments like zero correction play a crucial part in obtaining the true measurement. By understanding how to read a vernier scale correctly, one ensures measurements are precise and trustworthy.