Physics Expanded Summary
Chapter 1: Measurement and Units
Definitions:
Physics: The study of matter, energy, and their interactions.
Physical Quantities: Categorized as Fundamental (e.g., length, time) and Derived (e.g., speed).
Measurement:
Measurement involves comparing an unknown quantity with a standard. SI Units are universally accepted for consistency.
SI Units:
- Length: meter (m)
- Mass: kilogram (kg)
- Time: second (s)
- Electric Current: ampere (A)
- Temperature: kelvin (K)
- Amount of Substance: mole (mol)
- Luminous Intensity: candela (cd)
Examples:
- Convert 25 kilometers to meters: 25 km × 1000 = 25,000 meters.
- Calculate the area of a square with side 5 m: Area = side × side = 5 × 5 = 25 m².
- A liquid has a mass of 500 grams and occupies 250 mL. Find its density: 2 g/mL.
- Convert 5000 seconds to hours: 5000 / 3600 ≈ 1.39 hours.
- Car travels 120 km in 2 hours. Calculate speed: 60 km/h.
Chapter 2: Sound and Magnetism
Sound:
Produced by vibrations and propagates as mechanical waves. Requires a medium to travel.
Magnetism:
Magnets have poles (north and south) and produce magnetic fields.
Examples:
- Velocity of a sound wave (500 Hz, 2 m): v = 500 × 2 = 1000 m/s.
- The frequency of a sound wave is 2000 Hz. Period = 1/2000 = 0.0005 s.
- A wave travels 20 m in 4 seconds. Speed = 20/4 = 5 m/s.
Chapter 3: Thermodynamics
Definitions:
Thermodynamics is the study of heat transfer and energy transformations.
Heat Transfer:
- Conduction: Direct contact (e.g., hot pan).
- Convection: Fluid movement (e.g., boiling water).
- Radiation: No medium required (e.g., sunlight).
Examples:
- Convert 45°C to Kelvin: 45 + 273 = 318 K.
- Calculate heat for 2 kg of water, 10°C change: 84,000 J.
Chapter 4: Electricity
Definitions:
Electricity involves the flow of charges, driven by voltage and opposed by resistance.
Ohm's Law:
V = IR. Helps calculate voltage, current, or resistance.
Examples:
- Circuit with 12 V and 4 ohm: Current = 12/4 = 3 A.
- Resistors in parallel (6 ohm, 3 ohm): Total = 2 ohms.
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