FISIKA KELAS X | KETIDAKPASTIAN PENGUKURAN TUNGGAL. PART 2

Summary

This video explains the concept of measurement uncertainty in physics, focusing on how errors arise from factors like instrument limitations and observer positioning. It covers the process of reporting results with uncertainty, using the formula: Measurement result = X ± ΔX. The video provides examples of single measurements with instruments like rulers, calipers, and micrometers, demonstrating how to calculate and express uncertainty. It emphasizes the importance of understanding the least count of measuring devices and applying it to report accurate results. The goal is to teach students how to handle and express measurement uncertainties properly.

Takeaways

• 😀 Measurement uncertainty is a natural part of every physical measurement due to factors like instrument limitations and observer skill.
• 😀 The formula for expressing measurement results with uncertainty is: Measurement result = X ± ΔX, where X is the measured value and ΔX is the uncertainty.
• 😀 Uncertainty (ΔX) is typically calculated as half of the smallest scale value (NST) of the instrument used.
• 😀 In the case of a ruler with an NST of 0.1 cm, the uncertainty is calculated as 0.05 cm.
• 😀 Measurement results must be written with the correct number of significant digits, considering the uncertainty in the last decimal place.
• 😀 When using a vernier caliper with an NST of 0.01 cm, the uncertainty in measurements is 0.005 cm.
• 😀 For a micrometer screw gauge with an NST of 0.01 mm, the uncertainty is 0.0005 mm.
• 😀 Measurement results should indicate the range in which the true value lies, based on the measured value ± uncertainty.
• 😀 The uncertainty is influenced by the precision of the instrument, like how fine the scale divisions are (e.g., 0.1 mm, 0.01 cm, etc.).
• 😀 The takeaway from all examples is that precise measurement requires both accurate reading of the instrument and correct uncertainty calculation.

Q & A

What is the main concept discussed in the video?

The main concept discussed in the video is measurement uncertainties in physics and how to write the result of a measurement, including its uncertainty.

How is uncertainty represented in a measurement?

Uncertainty is represented as the difference between the measured value (X) and the uncertainty (ΔX), written as X ± ΔX.

What formula is used to calculate uncertainty in a measurement?

The formula for calculating uncertainty is ΔX = 1/2 * NST, where NST is the smallest scale of the measuring instrument.

What does the symbol 'X' represent in the formula?

The symbol 'X' represents the measured value in the result of the measurement.

How does the precision of a measuring tool affect uncertainty?

The precision of a measuring tool determines the smallest scale (NST), and this scale is directly related to the uncertainty. A tool with a finer precision results in a smaller uncertainty.

What is the uncertainty for a measurement using a ruler with an NST of 0.1 cm?

For a ruler with an NST of 0.1 cm, the uncertainty (ΔX) would be 0.05 cm.

Can uncertainty be expressed for multiple measurements or only single measurements?

The method described for writing uncertainty applies only to single measurements, not to multiple measurements or averages.

What is the correct format for writing the result of a single measurement?

The correct format for writing the result of a single measurement is 'X ± ΔX', where X is the measured value and ΔX is the uncertainty.

Why is it important to consider the precision of the measuring instrument when writing results?

Considering the precision of the instrument ensures that the uncertainty matches the tool's scale, allowing for a more accurate and reliable representation of the measurement.

How should the result of a measurement be written if the uncertainty is 0.05 cm and the measured value is 3.1 cm?

The result should be written as 3.1 ± 0.05 cm, meaning the true value is between 3.05 cm and 3.15 cm.