Errors in measurements
Accurate measurements are essential for scientific research, Engineering and many other fields. Analogue instruments such as rulers, Vernier callipers, micrometer screw gauges, thermometers, balances, and protractors, as well as digital instruments such as voltmeters and ammeters, enable us to quantify and compare physical quantities precisely. You must learn the proper usage of the instru...
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Time limit: 100 minutes
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Multiple attempts are not allowed
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All questions must be answered to submit
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Question 1
You are using a metre rule to measure the length of a wooden stick. When you take the reading, you realize that your eye was slightly above the measurement mark, thus leading to an inaccurate reading. Question: What type of error did you experience in this measurement process?
Explanation
The scenario describes an instance of parallax error, which occurs when the observer's eye is not aligned with the measurement mark. This is common when reading analog scales.
Question 2
You are tasked with measuring the angle between two walls using a protractor. However, you mistakenly place the protractor's baseline away from the vertex of the angle. Question: What kind of erroneous result does this placement likely lead to?
Explanation
Placing the protractor's baseline away from the vertex leads to an incorrect angle measurement, demonstrating the importance of proper placement.
Question 3
When using an electronic balance, you forgot to zero the balance before weighing your sample. In turn, your mass reading is inaccurate. Question: What is the recommended action to ensure an accurate reading in this scenario?
Explanation
The correct action is to press the 'tare' or 'zero' button before weighing to reset the balance, ensuring an accurate measurement.
Question 4
Using a vernier caliper, you misread the scale because you failed to align the zero mark properly. Question: How can you improve your measurement accuracy with this instrument?
Explanation
Carefully aligning the zero of the vernier scale with the main scale ensures that you read the measurements correctly, minimizing errors.
Question 5
While measuring with a micrometer screw gauge, you applied excessive force while turning the ratchet, which affected your measurement. Question: What is the proper technique to ensure consistent readings with this tool?
Explanation
Gently using the ratchet stop helps ensure consistent measurements and prevents compression of the object being measured, resulting in accurate readings.
Question 6
During a physics experiment to measure the length of a wooden plank, a student uses a metre rule. However, they accidentally position their eye at an angle, rather than directly above the marking. This leads to a parallax error, resulting in an inaccurate measurement. What is the best way to correct this error when using a metre rule? Question: How should the student adjust their measurement technique to ensure accuracy while using the metre rule?
Explanation
To eliminate parallax error, the eye must be level with the mark on the metre rule for an accurate reading, ensuring that the reading is directly aligned with the measurement scale. Other approaches may introduce bias or inaccuracy due to improper measurement techniques.
Question 7
In a laboratory setting, a student is tasked with measuring the angle of a triangular piece of metal using a protractor. They place the baseline of the protractor incorrectly such that it does not align with the vertex of the angle, resulting in flawed angle readings. What crucial step should the student take before measuring the angle? Question: Which action is necessary to ensure that the angle is measured accurately with the protractor?
Explanation
The correct alignment of the protractor's baseline with the vertex of the angle is essential for accurate measurement, directly influencing the reliability of the data. Misalignment can lead to systematic errors, while other options do not ensure accuracy.
Question 8
A physics student is recording the mass of a sample using an electronic balance but forgets to zero the balance before placing the object on it. As a result, the readings are inaccurate. What action should the student take to avoid this common mistake in future experiments? Question: What procedure is necessary before using an electronic balance to ensure correct mass measurements?
Explanation
Pressing the 'tare' or 'zero' button before measuring allows the student to eliminate any weight of the container or previous measurements, ensuring accurate readings for the sample. The other options are ineffective or irrelevant to ensuring accuracy.
Question 9
While using a micrometer screw gauge, a student applies excessive force while turning the ratchet to measure the diameter of a small ball. This action compresses the ball, resulting in a smaller measurement than accurate. What should the student focus on to enhance measurement consistency and accuracy in future uses of the micrometer screw gauge? Question: What is the recommended practice for taking measurements with a micrometer screw gauge to avoid compression errors?
Explanation
Using the ratchet stop gently prevents over-compression of the object being measured, leading to more accurate and consistent measurements. Other methods may compromise the integrity of the measurements and lead to errors.
Question 10
During a physics experiment measuring the length of a metal rod using a metre rule, a student notices that their reading appears erroneous. Upon review, the student realizes their eye was not level with the measurement mark while reading. Question: What should the student do to improve measurement accuracy in the future?
Explanation
The correct approach is to ensure proper alignment of the eye with the measurement mark to avoid parallax errors in future readings. Other options either ignore the core issue or introduce further errors into the measurement process.
Question 11
A student is tasked with measuring an angle using a protractor. However, they notice that the protractor’s baseline is not aligned with the vertex of the angle, leading to incorrect measurements. Question: Which action should the student take to rectify this error?
Explanation
Aligning the protractor's baseline with the vertex is crucial for obtaining an accurate angle measurement. Incorrect alignments, averaging, or simply switching tools without resolving alignment errors will still generate inaccurate results.
Question 12
An engineering team is using an electronic balance to measure the mass of various samples. They often find discrepancies in their readings because they forget to zero the balance before weighing an object. Question: What protocol should the team implement to enhance their measurement accuracy with the electronic balance?
Explanation
Pressing the 'tare' button before each measurement is essential for improving accuracy as it ensures that only the mass of the object is displayed. Inadequate habits will lead to continuous inaccuracies in their measurements.
Question 13
A student encounters difficulty reading the Vernier scale on a Vernier calliper during a measurement task. They realize they are misreading the scale by not aligning the zero mark correctly. Question: What corrective measure should the student adopt to enhance their reading accuracy with the Vernier calliper?
Explanation
Aligning the zero of the Vernier scale with the main scale is vital for taking precise measurements with this instrument. Other options suggest practices that can lead to additional errors or lack the necessary precision.
Question 14
While utilizing a micrometer screw gauge in a lab activity, a student applies excessive force while turning the ratchet, leading to distorted measurements. They realize this is a common mistake when taking measurements. Question: What should they focus on to ensure they obtain consistent and accurate measurements with the micrometer?
Explanation
Gently using the ratchet stop ensures appropriate force is applied, leading to accurate and consistent measurements. Other approaches fail to address the core of the problem, instead perpetuating adverse measurement practices.
Question 15
During a physics lab experiment, a student uses a metre rule to measure the length of a desk but is standing at an angle. As they take the reading, they notice a discrepancy in their measurement understanding that parallax error may have occurred. Question: What is the appropriate solution for avoiding this type of error during measurement?
Explanation
The correct approach is to ensure the eye is level with the measurement mark to prevent parallax error. The other options do not effectively address the issue of misalignment in this context.
Question 16
In a geometry class, students are asked to measure angles using a protractor. One group of students places the baseline of the protractor off the angle’s vertex while measuring. They obtain an angle measurement that seems inaccurate. Question: What should the students do to correct their measurement technique?
Explanation
Aligning the protractor’s baseline with the vertex of the angle is necessary for accurate angle measurement. The other options suggest methods that will not resolve the fundamental issue.
Question 17
In preparation for an experiment, a student forgets to zero their electronic balance before measuring the mass of a chemical sample. As they record the mass, they notice it seems too high. Question: What is the proper procedure the student should have followed before taking the mass measurement?
Explanation
Pressing the 'tare' or 'zero' button is essential for accurate mass measurements, as it resets the balance to account for any residual weight. The other options do not address the need to zero the balance.
Question 18
When using a Vernier caliper, a student misreads the scale by not aligning the zero mark properly and incorrectly identifies the reading. After discussing this with the instructor, they realize they need to be more careful. Question: What is the critical action the student should take to ensure accurate readings with the Vernier caliper?
Explanation
The correct practice is to align the zero of the vernier scale with the main scale to avoid misreading. Other options disregard the fundamental method of using the Vernier caliper accurately.
Question 19
A student is using a micrometer screw gauge to measure the diameter of a small wire. While turning the ratchet, they apply excessive force, which results in a compressed measurement. Question: What should the student do to maintain accuracy while using the micrometer screw gauge?
Explanation
Gently using the ratchet stop is essential for obtaining accurate measurements without damaging the object being measured. The other options lead to inaccuracies or improper usage of the tool.
Question 20
During a physics lab session, several students are tasked with measuring the length of a wooden plank using a metre rule. One student consistently obtains readings that are slightly longer than the actual length of the plank. Upon review, it is discovered that they were not correctly aligning their eye level with the measurement mark. Question: What error was made by the student, and what is the best solution to correct it?
Explanation
The student's error resulted from the misalignment of their eye level with the measurement mark on the metre rule, leading to a parallax error. To correct this issue, they should consistently ensure that their eye is directly above the measurement mark to achieve accurate readings. Other options are not applicable to this specific scenario, as they pertain to different measuring instruments or irrelevant contexts.