Questions and Answers
What is the main characteristic that defines a physical quantity?
Which of the following is an example of a derived quantity?
What is the purpose of a standard unit in measurement?
What type of measurement involves measuring a quantity directly using an instrument?
Signup and view all the answers
What is the main difference between systematic error and random error?
Signup and view all the answers
What is the term used to describe the range of values within which the true value of a measurement is likely to lie?
Signup and view all the answers
What is the term used to describe the closeness of repeated measurements to each other?
Signup and view all the answers
Which of the following is an example of a non-SI unit?
Signup and view all the answers
Study Notes
Physical Quantities
- A physical quantity is a characteristic of an object or phenomenon that can be measured
- Examples: length, mass, time, temperature, electric current
- Physical quantities can be classified into two categories:
- Fundamental quantities: cannot be expressed in terms of other quantities (e.g. length, mass, time)
- Derived quantities: can be expressed in terms of fundamental quantities (e.g. speed, force, energy)
Measurement
- Measurement: the process of assigning a numerical value to a physical quantity
- Measurement involves comparison with a standard unit
- Units:
- SI units (International System of Units): standardized units used globally
- Non-SI units: units that are not part of the SI system (e.g. inches, pounds)
- Measurement instruments:
- Direct measurement: measuring a quantity directly using an instrument (e.g. ruler, thermometer)
- Indirect measurement: measuring a quantity indirectly by measuring other related quantities (e.g. measuring speed by measuring distance and time)
Types of Measurement
- Direct measurement: measuring a quantity directly using an instrument
- Indirect measurement: measuring a quantity indirectly by measuring other related quantities
- Fundamental measurement: measuring a fundamental quantity (e.g. length, mass, time)
- Derived measurement: measuring a derived quantity (e.g. speed, force, energy)
Measurement Uncertainty
- Systematic error: error that occurs due to a flaw in the measurement instrument or technique
- Random error: error that occurs due to chance or unpredictable factors
- Uncertainty: the range of values within which the true value of a measurement is likely to lie
- Precision: the closeness of repeated measurements to each other
- Accuracy: the closeness of a measurement to the true value
Physical Quantities
- A physical quantity is a characteristic of an object or phenomenon that can be measured, such as length, mass, time, temperature, and electric current.
- Physical quantities can be classified into two categories: fundamental quantities and derived quantities.
- Fundamental quantities cannot be expressed in terms of other quantities, whereas derived quantities can be expressed in terms of fundamental quantities.
Measurement
- Measurement is the process of assigning a numerical value to a physical quantity, which involves comparison with a standard unit.
- Standard units used globally are called SI units (International System of Units), while units that are not part of the SI system are called non-SI units.
- Measurement instruments can be used for direct measurement, which involves measuring a quantity directly, or indirect measurement, which involves measuring a quantity indirectly by measuring other related quantities.
Types of Measurement
- Direct measurement involves measuring a quantity directly using an instrument.
- Indirect measurement involves measuring a quantity indirectly by measuring other related quantities.
- Fundamental measurement involves measuring a fundamental quantity, such as length, mass, or time.
- Derived measurement involves measuring a derived quantity, such as speed, force, or energy.
Measurement Uncertainty
- Systematic error occurs due to a flaw in the measurement instrument or technique.
- Random error occurs due to chance or unpredictable factors.
- Uncertainty is the range of values within which the true value of a measurement is likely to lie.
- Precision refers to the closeness of repeated measurements to each other.
- Accuracy refers to the closeness of a measurement to the true value.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about physical quantities, their classification, and the process of measurement. Understand fundamental and derived quantities.