Physics Chapter 1: Measurements and Errors

Cylinder Calculations

• Length of cylinder: 8.9 cm
• Radius of cylinder: 2.543 cm
• Curved surface area and volume should be expressed with appropriate significant figures.

Density Calculation

• Volume of body: 14.56 cm³
• Mass of body: 20.589 g
• Density is calculated and rounded to three significant figures.

Errors in Measurement

• Accuracy and precision (consistency) are critical in scientific measurements.
• Accuracy refers to the difference between the measured value and the true value, while precision is the difference between observed values and their mean.
• Observations by three observers (A, B, C) can show varying levels of accuracy and precision:
  • Observer A: Accurate and precise data
  • Observer B: Accurate but inconsistent (precise)
  • Observer C: Neither accurate nor precise data.

Types of Measurement Errors

• Systematic errors: Arise from defined rules or conditions.
  • Instrumental errors: Result from defects in measuring instruments (e.g., zero error or faulty graduation).
  • Errors due to external causes: Caused by variations in external conditions affecting measurements.

Notable Scientific Constants

• Charge of electron: 1.6 x 10⁻¹⁹ C
  • Order of magnitude: (10^{19} C)
• Mass of Earth: 5.983 x 10²⁴ kg
  • Order of magnitude: (10^{24} kg)
• Radius of Earth: 6.378 x 10⁶ m
  • Order of magnitude: (10^{7} m)

Importance of Measurement Accuracy

• Some inaccuracies and inconsistencies are inevitable despite careful measurement efforts.
• Identifying types and causes of errors is vital for minimizing inaccuracies in scientific research.