Fundamentals of Electricity: Quantities, Circuits, and Measurement
1 – Basic Electrical Quantities
The fundamental quantities that characterize electrical power are voltage, current, resistance, and power.
Voltage
The energy with which a generator is able to push electrons through a circuit is called voltage or electromotive force (EMF).
Voltage is also known as potential difference (PD) and is measured in volts (V).
Electric Current
Electric current is the rate of flow of electric charge through a circuit per unit time.
Electric current, also called intensity, is measured
Read MoreThe Sun’s Inner Workings: Energy, Structure, and Activity
The Sun: Our Star’s Energy, Structure, and Activity
Stellar Energy: The Power of Nuclear Fusion
Stars are powered by nuclear reactions involving hydrogen (H) and helium (He).
The source of stellar energy is nuclear fusion: the combining of lighter nuclei into heavier ones. The immense amount of energy released is described by Einstein’s famous equation: E = mc2.
The greater the nuclear binding energy, the more stable the nucleus.
Conditions for Nuclear Fusion
Nuclear fusion only occurs at temperatures
Read MoreEssential Physics Formulas and Concepts
Energy Principles and Equations
Kinetic Energy (J) = ½ × Mass (kg) × Speed (m/s)² → Ek = ½mv²
Gravitational Potential Energy (J) = Mass (kg) × Gravitational Field Strength (N/kg) × Height (m) → Ep = mgh
Elastic Potential Energy (J) = ½ × Spring Constant (N/m) × Extension² (m) → E = ½ke²
Change in Thermal Energy (J) = Mass (kg) × Specific Heat Capacity (J/kg°C) × Temperature Change (°C) → ∆E = mc∆θ
Rate of Doing Work and Power
- Power (W) = Energy Transferred (J) / Time (s)
Cosmic Foundations of Life: Astronomy & Astrobiology Concepts
The Science of Life in the Universe
- The possibility of extraterrestrial life was first considered: many thousands of years ago during ancient times.
- The methods of modern science were originated by the: Greeks.
Key Astronomical Models & Laws
- Geocentric Model
- A spherical Earth at the center of the universe, surrounded by a celestial sphere.
- Heliocentric (Sun-centered) Model
- Describes the relative motion between Earth and other planets in their orbits.
- Stellar Parallax
- The apparent shift in position of
Black vs White: Heat Absorption & Temperature Rise
Hypothesis: Black vs. White Heat Absorption
The black can will heat up faster than the white can because black surfaces absorb more light energy, which is then converted into heat, while white surfaces reflect more light.
Experimental Observations
The black can increased in temperature more quickly than the white can. This is due to the color black absorbing light energy while the color white reflects light. This causes the black can to heat up much faster than the white. Additionally, heat is transferred
Read MorePhysics Formulas and Concepts Summary
Moments of Inertia
I = m * d². System for discrete masses: I = Σmᵢ * dᵢ². System for continuous bodies: I = ∫ (d² * dm). Steiner’s Theorem (Parallel Axis Theorem): Ia = Ib + m * d² (where Ib is the moment of inertia about an axis passing through the center of mass G, and the axis ‘a’ is parallel to ‘b’ at a distance ‘d’).
Kinematics of a Point
Position
Defined by a path-time law.
Path (Trajectory)
The set of positions of point P. Can be the intersection of two surfaces. Eliminate time ‘t’ from
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