Measurement Techniques in Physics

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the range of objects that can be measured using a micrometre screw gauge?

0.01 mm

What is the maximum length that can be measured using a micrometre screw gauge?

0.01 mm

What is the range of measurements that a vernier scale can be used to make?

0.1 mm

Explain the difference between accuracy and precision in a measurement.

Accuracy refers to how close a measurement is to the actual or true value of a quantity. Precision refers to how close repeated measurements are to each other, regardless of whether they are close to the true value. In other words, accuracy is about the correctness of a measurement, while precision is about the consistency or reproducibility of the measurement. Signup and view all the answers

What is the purpose of a Vernier scale? What are its advantages?

A Vernier scale is used to measure the small distances and lengths with high accuracy. Vernier scale is used for measuring the length of an object by magnifying the graduations of the main scale, enabling us to read the minor divisions with greater precision. It allows for more precise measurements in applications like caliper and micrometer screw gauges, compared to using a standard ruler. Signup and view all the answers

If range given e.g. $0$ to $20$, try to get a measurement from a large spread of the range. What is the purpose of this?

To ensure that the measurement is as accurate as possible. (D) Signup and view all the answers

Systematic error is a type of error that can be eliminated by repeating or averaging the measurement.

False (B) Signup and view all the answers

Accuracy refers to the degree of agreement between the result of a measurement and the true value of the quantity.

True (A) Signup and view all the answers

Random error can be reduced by repeating and averaging the measurements.

True (A) Signup and view all the answers

Precision refers to the consistency of repeated measurements of the same quantity, regardless of whether it is correct or not.

True (A) Signup and view all the answers

When values are added or subtracted, add absolute error to find the uncertainty in the result.

True (A) Signup and view all the answers

Give an example of when you would add percentage errors while calculating the combined uncertainty.

When quantities are multiplied or divided, add the percentage uncertainties to find the overall uncertainty in the result. For example, if you are calculating the area of a rectangle and you know the length and width with their uncertainties, you would add the percentage uncertainties in the length and width to find the percentage uncertainty in the area. Signup and view all the answers

Give an example of when you would multiply the percentage error with the power while calculating the combined uncertainty.

When a value is raised to a power, multiply the percentage uncertainty by the power to obtain the overall percentage uncertainty. For instance, if you are calculating the volume of a sphere, which is proportional to the cube of the radius, you would multiply the percentage uncertainty in the radius by three to find the percentage uncertainty in the volume. Signup and view all the answers

What is the difference between actual error and the number of decimal places used for a quantity?

The actual error is the maximum uncertainty in a measurement and is typically expressed to one significant figure. The number of decimal places used for a quantity in a calculated result should match the number of decimal places in the actual error. For example, if the actual error is ±0.1 mm, the result should be given to one decimal place. Signup and view all the answers

When recording a calculated quantity, the final result should have the same number of significant figures as the measured quantity.

False (B) Signup and view all the answers

In an experiment, how can you minimize random errors in your measurements?

To minimize random errors, you need to repeat the measurements multiple times and then take the average of all the readings. Repeating measurements helps to average out the random fluctuations in the readings. Additionally, you can use more precise measuring instruments. Signup and view all the answers

When calculating the area of a circle, the actual error is the difference between the measured area and the theoretical area of the circle.

True (A) Signup and view all the answers

In general, how many readings should you take in an experiment for an accurate and reliable measurement?

It is generally recommended to take at least three readings in an experiment to ensure accurate and reliable measurements. Taking multiple readings helps to minimize systematic errors and random errors in measurements. Signup and view all the answers

Give a basic example of a systematic error in an experiment.

An example of a systematic error could be an improperly calibrated scale. If the scale is consistently reading 0.2 cm too high, then every measurement taken using that scale will be off by 0.2 cm. This error would apply to all measurements, introducing a consistent bias. Signup and view all the answers

Give a basic example of a random error in an experiment.

One example of a random error is the slight variability in how you read a scale. When reading a scale, you might judge the position of the pointer slightly differently each time, leading to variations in readings. These variations are random and not systematic. Signup and view all the answers

Flashcards

Micrometer Screw Gauge

A tool for measuring objects up to 0.1 mm.

Systematic Error

A consistent error in measurement, always in the same direction.