Chapter 1

Lecturer Information

  • Name: Mr. D. Tembo

  • Qualifications:

    • Bachelor of Science in Physics

    • Master of Science in Particle and Nuclear Physics

  • Specialization: Nuclear Physicist/Particle Physicist

Chapter 1: Units and Measurements

1.1: Units for Measurements

  • Physical Quantities: Measured and expressed in laws.

  • Unit: Reference standard for comparison.Measurement values compared to reference unit.

1.2: Magnitude

  • Number of times reference standard exists in the physical quantity.

1.3: Fundamental Physical Quantities

  • Fundamental Units: Independent quantities; examples include mass, length, and time.

1.4: Derived Physical Quantities

  • Derived from fundamentals; examples include area (m²), pressure (Pa), density (kg/m³), and speed.

  • Units:

    • Force: 1 N = 1 kg·m/s²

    • Pressure: 1 Pa = 1 kg/(m·s²)

1.5: The International System of Units (SI)

Quantity

Unit Name

Unit Symbol

Length

Meter

m

Time

Second

s

Mass

Kilogram

kg

Temperature

Kelvin

K

Electric Current

Ampere

A

Amount of Substance

Mole

mol

Luminous Intensity

Candela

Cd

1.6: Prefixes

1.6.1: Very Big Numbers

Factor

Prefix

Symbol

10²⁴

Yotta-

Y

10²¹

Zetta-

Z

10¹⁸

Exa-

E

10¹⁵

Peta-

P

10¹²

Tera-

T

10⁹

Giga-

G

10⁶

Mega-

M

10³

Kilo

K

10²

Hecta

H

10¹

Deca-

Da

1.6.2: Very Small Numbers

Factor

Prefix

Symbol

10⁻²⁴

Yocto-

y

10⁻²¹

Zepto-

z

10⁻¹⁸

Atto-

a

10⁻¹⁵

Femto-

f

10⁻¹²

Pico-

p

10⁻⁹

Nano-

n

10⁻⁶

Micro-

µ

10⁻³

Milli-

m

10⁻²

Centi-

c

10⁻¹

Deci-

d

1.7: Conversion of Units

  • Conversion factors include:

    • 1 mile = 1609 meters

    • 1 year = 3.1537 x 10⁷ seconds

    • 1 kilometer = 1000 meters

    • 1 meter = 39.37 inches

    • 1 tonne = 1000 kilograms

    • 1 yard = 36 inches

1.8: Dimensional Analysis

  • Dimensional Formulae:

    • Area: [L²]

    • Volume: [L³]

    • Density: [M][L⁻³]

    • Speed: [L][T⁻¹]

    • Force: [M][L][T⁻²]

    • Pressure: [M][L⁻¹][T⁻²]

    • Work: [M][L²][T⁻²]

    • Power: [M][L²][T⁻³]

1.8.1: Principle of Homogeneity of Dimensions

  • Equations must maintain dimensional consistency.

1.8.2: Applications of Dimensional Analysis

  • Determine units for physical quantities, check equation accuracy, convert units.

1.8.3: Limitations of Dimensional Analysis

  • Cannot deduce dimensionless constants, applicable for product types only.

1.9: Significant Figures

  • Indicates confidence level in measurements.

  • Rules:

    • Non-zero digits are significant.

    • Zeros between non-zero digits are significant.

    • Leading zeros are never significant.

1.10: Rounding Off

  • Follow rules for rounding digits based on value.

1.11: Accuracy and Errors in Measurements

  • Types of Errors:

    • Constant Error

    • Systematic Error

    • Random Error

    • Gross Error

1.12: Absolute, Mean Absolute, Relative, and Percentage Errors

  • Define errors based on true values and measurements.

1.13: Density and Atomic Mass

  • Density (𝜌): Mass per unit volume; example of copper: 8.93 g/cm³.

1.14: Order of Magnitude Calculation

  • Expresses quantity in powers of ten; rules for rounding apply.

Practice Questions

  • Various problems relating to density, conversions, calculations involving errors and significant figures.