Introduction to Units and Measurement
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Questions and Answers

In the International System of Units (SI), how many base units are there?

  • Ten
  • Nine
  • Seven (correct)
  • Five

    • Which of the following is NOT one of the SI base units?

  • Newton (correct)
  • Meter
  • Kilogram
  • Second

    • The Système Internationale d'Unités (SI) is an internationally accepted system of units for measurement that utilizes a decimal system.

    True

    Which of the following units is NOT part of the SI system?

    <p>Centimeter</p> Signup and view all the answers

    What is the SI unit for plane angle?

    <p>radian</p> Signup and view all the answers

    What is the symbol for the base unit of luminous intensity?

    <p>cd</p> Signup and view all the answers

    The ______ is a unit of length that is equal to 10-10 m.

    <p>angstrom</p> Signup and view all the answers

    The speed of light in vacuum is defined as a fixed numerical value in the SI unit system.

    <p>True</p> Signup and view all the answers

    What are the dimensions of force in terms of the fundamental quantities (M, L, T)?

    <p>[MLT-2]</p> Signup and view all the answers

    The ______ is the SI unit of electric current.

    <p>ampere</p> Signup and view all the answers

    What is the importance of 'dimensional homogeneity' in equations involving physical quantities?

    <p>Dimensional homogeneity ensures consistency and correctness in an equation.</p> Signup and view all the answers

    What type of physical quantities are dimensionless?

    <p>Pure numbers, ratios of similar quantities, and angles.</p> Signup and view all the answers

    Dimensional analysis can determine the exact value of a proportionality constant in an equation?

    <p>False</p> Signup and view all the answers

    Give an example of a physical quantity that is measured in units of 'radian/second' and describe its significance.

    <p>Angular velocity (ω) is measured in radians per second.</p> Signup and view all the answers

    What is the standard for comparing the size of objects called?

    <p>Unit of measurement</p> Signup and view all the answers

    When reporting a measurement, what does 'significant figures' indicate?

    <p>Both A and B</p> Signup and view all the answers

    When performing multiplication or division with measurements, the final result should have the same number of decimal places as the measurement with the fewest decimal places.

    <p>False</p> Signup and view all the answers

    The process of rounding off a number to a certain number of significant figures can introduce errors or uncertainties into a calculation.

    <p>True</p> Signup and view all the answers

    Which of the following is NOT a guideline for determining the uncertainty or error in a measured value?

    <p>Always round up the final answer to the next significant figure</p> Signup and view all the answers

    Study Notes

    Introduction to Units and Measurement

    • Measurement involves comparing a physical quantity with a standard unit.
    • The result is a numerical value accompanied by a unit.
    • A system of units is a complete set of both base and derived units.

    International System of Units (SI)

    • The internationally accepted system of units.
    • Base units for length, mass, and time in different systems:
      • CGS: centimeter, gram, second
      • FPS: foot, pound, second
      • MKS: meter, kilogram, second
    • SI base units:
      • Length (meter, m)
      • Mass (kilogram, kg)
      • Time (second, s)
      • Electric current (ampere, A)
      • Thermodynamic temperature (kelvin, K)
      • Amount of substance (mole, mol)
      • Luminous intensity (candela, cd)

    Significant Figures

    • Significant figures represent reliable digits in a measurement plus the first uncertain digit
    • All non-zero digits are significant
    • Zeros between non-zero digits are significant, regardless of decimal location.
    • Zeros to the right of a decimal point and to the right of a non-zero digit are significant.
    • Zeros to the left of the first non-zero digit in a number less than 1 are not significant.
    • Terminal zeros in a whole number without a decimal are not significant.
    • Terminal zeros in a decimal are significant.

    Dimensional Formulae and Equations

    • Dimensional formula: Expression showing base units and exponents for a quantity.
    • Dimensional equation: Equation showing equality of dimensions on both sides
    • Dimensions are independent of numerical values

    Dimensional Analysis

    • Checking the consistency of equations
    • Only quantities with the same dimensions can be added or subtracted.
    • Dimensions on both sides of an equation must be the same.
    • Dimensional analysis can check the correctness of equations and derive relationships.

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    Description

    This quiz covers the fundamentals of units and measurement, including the International System of Units (SI) and the concept of significant figures. Test your knowledge on base and derived units, as well as the importance of precise measurements in scientific contexts.

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