Measurements and Errors in Physics

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Listen to an AI-generated conversation about this lesson

Questions and Answers

Why is the SI system considered an improvement over previous systems of units like MKS or CGS?

  • It introduces additional units to cover a broader range of physical quantities and aims for universal acceptance. (correct)
  • It relies solely on derived quantities, simplifying measurements.
  • It reduces the number of fundamental quantities to only three.
  • It uses feet, pounds, and seconds, which are more practical for everyday measurements.

A student measures the side of a square to be 5.0 cm using a ruler with millimeter markings. What is the area of the square, expressed with the correct number of significant figures?

  • 25.0 cm² (correct)
  • 25.000 cm²
  • 25.00 cm²
  • 25 cm²

When using the parallax method to measure the distance to a star, which of the following changes would lead to a more accurate distance measurement?

  • Using a baseline (b) equal to the star's diameter.
  • Decreasing the baseline (b) and measuring a smaller parallax angle.
  • Measuring the parallax angle in degrees instead of radians.
  • Increasing the baseline (b) and measuring a larger parallax angle. (correct)

Why is it impossible to completely eliminate random errors in experimental measurements?

<p>Random errors arise from unpredictable variations in the measurement process. (C)</p> Signup and view all the answers

In the context of dimensional analysis, what does it mean for an equation to be 'dimensionally consistent'?

<p>The dimensions of each term on both sides of the equation are the same. (D)</p> Signup and view all the answers

A student is asked to calculate the kinetic energy (KE) of an object. They correctly recall the formula KE = (1/2)mv², but mistakenly use grams for mass (m) and km/h for velocity (v). What is the most immediate consequence of this error?

<p>The calculated KE will have incorrect dimensions. (D)</p> Signup and view all the answers

During an experiment, a student measures a voltage (V) and a current (I) to determine the resistance (R) of a resistor using Ohm's Law (R = V/I). If the percentage error in the voltage measurement is 3% and the percentage error in the current measurement is 2%, what is the percentage error in the calculated resistance?

<p>5% (B)</p> Signup and view all the answers

Which of the following statements correctly differentiates between 'accuracy' and 'precision' in the context of measurement?

<p>Accuracy indicates how close a measurement is to the true value, while precision indicates the repeatability or consistency of the measurement. (D)</p> Signup and view all the answers

A student uses a Vernier caliper to measure the diameter of a steel ball. The main scale reading is 2.5 cm, and the Vernier scale division that coincides with a main scale division is 6. If the least count of the Vernier caliper is 0.01 cm, what is the measured diameter of the steel ball?

<p>2.56 cm (D)</p> Signup and view all the answers

Consider the equation $v = at + b/t + c$, where $v$ is velocity and $t$ is time. What are the dimensions of the constants $a$, $b$, and $c$, respectively?

<p>$L/T^2$, $L$, $L/T$ (C)</p> Signup and view all the answers

Flashcards

Unit

The standard for measurement of a physical quantity, characterized by being well-defined, universally accepted, easily reproducible, and invariable.

SI System

A system of units composed of seven fundamental quantities (length, mass, time, temperature, current, luminous intensity, amount of substance) and two supplementary units (radian and steradian).

Astronomical Unit (AU)

The average distance between the Earth and the Sun, approximately 1.5 x 10^11 meters.

Parsec

The distance at which the average radius of the Earth's orbit subtends an angle of one arc second, equivalent to 3.08 x 10^16 meters.

Signup and view all the flashcards

Parallax Method

A method to measure large distances (e.g., to stars) by calculating distance based on the angle observed from different positions. Formula: d = b / θ.

Signup and view all the flashcards

Dimensional Formula

Expression showing the powers to which the fundamental quantities are raised to represent a physical quantity (e.g., V = LT^-1 for velocity).

Signup and view all the flashcards

Principle of Homogeneity

Principle stating that only quantities with the same dimensions/units can be added, subtracted, or compared.

Signup and view all the flashcards

Significant Figures

The digits in a measurement that are known with certainty plus one estimated digit, indicating the precision of the measurement.

Signup and view all the flashcards

Systematic Errors

Errors that are in one direction (systematic) and can be predictable, originating from instrument limitations or imperfect conditions.

Signup and view all the flashcards

Accuracy

The closeness of a measurement to the true or accepted value.

Signup and view all the flashcards

Study Notes

No new information to add, the existing notes contain all the information in the supplied text.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Mobile App
Open
Browser
Browser