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Questions and Answers
What are derived quantities and units?
What are derived quantities and units?
Derived quantities and units are those obtained by some simple combination of the fundamental quantities and units. They are thus dependent on the fundamental quantities and units.
What is the SI unit of density?
What is the SI unit of density?
kg.m^-3
What is the SI unit of acceleration?
What is the SI unit of acceleration?
m.s^-2
What is the unit of power?
What is the unit of power?
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What is the SI unit of frequency?
What is the SI unit of frequency?
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What is the SI unit of electric charge?
What is the SI unit of electric charge?
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What is the SI unit of electric potential difference?
What is the SI unit of electric potential difference?
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What is the SI unit of electric resistance?
What is the SI unit of electric resistance?
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What is the SI unit of electric capacitance?
What is the SI unit of electric capacitance?
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Derived quantities are independent of fundamental quantities.
Derived quantities are independent of fundamental quantities.
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The unit of power is Joule.
The unit of power is Joule.
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The unit of electric resistance is Volt.
The unit of electric resistance is Volt.
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The unit of frequency is Hertz.
The unit of frequency is Hertz.
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The unit of electric charge is Coulomb.
The unit of electric charge is Coulomb.
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The unit of electric potential difference is Ampere.
The unit of electric potential difference is Ampere.
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The unit of electric capacitance is Farad.
The unit of electric capacitance is Farad.
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What is the smallest graduation of the metre rule?
What is the smallest graduation of the metre rule?
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What is the estimated uncertainty when using a metre rule?
What is the estimated uncertainty when using a metre rule?
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What is the estimated uncertainty in a measurement of 21.55 cm using a metre rule?
What is the estimated uncertainty in a measurement of 21.55 cm using a metre rule?
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What are the tools commonly used to measure length in a secondary school physics laboratory?
What are the tools commonly used to measure length in a secondary school physics laboratory?
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Study Notes
Derived Quantities and Units
- Derived quantities are calculated from fundamental quantities
- They depend on fundamental quantities and units
- Examples of derived quantities and their units are summarized in Table 1.2
Table 1.3: Submultiples and Multiples
- Submultiples are fractions of a unit (e.g., decimeter = 10⁻¹ m)
- Multiples are multiples of a unit (e.g., kilometer = 10³ m)
- Prefixes are used to denote these multiples and submultiples (e.g., deci- (d), centi- (c), milli- (m), micro (μ), deca (da), hecto (h), kilo (k), Mega (M))
Measurements
- Measurements in physics are not perfectly precise
- Measured values are usually written with the correct number of significant figures
Significant Figures
- Significant figures indicate the precision of a measurement.
- They are all digits from the first non-zero digit to the last non-zero digit, plus final zeros after the decimal point
- Example :51.3 ± 0.1 cm (uncertainty 0.1 cm)
- Example : 51.30 (implied uncertainty 0.01 cm)
- The numbers in 51.20 cm and 51.3 cm both show different degrees of precision
Length Measurements
- Length is measured using metre rules, calipers, vernier calipers or micrometer screw gauges in lab.
- Metre rule graduations: in centimeters and millimeters
- Smallest graduation: 1mm or 0.1 cm
- Reading accuracy: up to half the smallest graduation (0.5 mm or 0.05 cm)
- Length measurement example : 21.55 ± 0.05 cm (uncertainty 0.05 cm)
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Description
This quiz covers derived quantities and their units as well as the concepts of significant figures in measurements. You'll explore how derived units relate to fundamental quantities and learn about the importance of precise measurements in physics. Test your understanding of multiples, submultiples, and significant figures.
