Light Physics Q&A: Luminous Flux, Intensity & Equations
Light Physics and Photometry Questions
Which term describes the total amount of visible light emitted by a source per unit time? — Luminous flux
What is the unit used to measure luminous flux? — Lumen
Illuminance describes: — the luminous flux received per unit area
What is the SI-related unit used to measure illuminance? — lux
One lux is equivalent to: — 1 lumen distributed over 1 m²
Luminous intensity describes: — how much light is emitted in a particular direction
Which unit is used to
Physics Kinematics: Scalars, Vectors, and SUVAT Equations
Physical Quantities Reference
| Symbol | Quantity | SI Unit | Type |
|---|---|---|---|
| s | Displacement / Distance | m (meters) | Vector / Scalar |
| u | Initial Velocity | m/s (meters per second) | Vector |
| v | Final Velocity / Speed | m/s (meters per second) | Vector / Scalar |
| a | Acceleration | m/s² (meters per second squared) | Vector |
| t | Time | s (seconds) | Scalar |
| m | Mass | kg (kilograms) | Scalar |
| W | Weight | N (Newtons) | Vector |
| g | Gravitational Field Strength | 9.8 N/kg (or m/s²) | Vector |
1. Scalars vs. Vectors
- Scalar: A physical quantity that has magnitude (size) only, with no direction.
- Examples: Distance
Essential Science Concepts: Atoms, Tissues, and Physics
1. Journey Inside the Atom
What is an atom?
The smallest basic unit of matter that makes up every element and chemical substance.
What are subatomic particles?
Particles smaller than an atom that form its internal structure. The three main particles are:
- Electrons
- Protons
- Neutrons
Define an electron
A negatively charged subatomic particle found outside the nucleus. Its relative charge is -1, and its mass is negligible (1/1836 of a proton).
Define a proton
A positively charged subatomic particle located inside
Read MoreFundamentals of Engineering Thermodynamics
Fundamentals of Thermodynamics
Thermodynamics is the branch of science that deals with energy (heat and work) transfer and its effect on the state or condition of a system.
Thermodynamics involves four fundamental laws:
- Zeroth Law: Deals with thermal equilibrium and relates to the concept of equality of temperature.
- First Law: Relates to the conservation of energy and introduces the concept of internal energy.
- Second Law: Relates to the direction of heat flow, dictates limits on the conversion of heat
Engineering Mechanics: Solved Problems in Statics and Dynamics
D’Alembert’s Principle: Elevator Dynamics
Given: Weight W = 1960 N, g = 9.81 m/s2. Mass m = 1960 / 9.81 = 199.8 kg (approx. 200 kg using g = 9.8 m/s2).
D’Alembert Equation: Tension T = m(g + a) for upward acceleration/downward deceleration, and T = m(g – a) for downward acceleration/upward deceleration.
- Moving UP with acceleration a = 2 m/s2: T = 1960 + (200 * 2) = 2360 N
- Moving UP with deceleration a = 1.5 m/s2: T = 1960 – (200 * 1.5) = 1660 N
- Moving DOWN with acceleration a = 2 m/s2: T = 1960 – (200
Mastering Rending Mechanics and Concept Ranks
How to Perform a Rending
- Decide the Effect: Determine the effect of your Rending, mixing and matching according to Concept descriptions. For example: Lightning Bolt/Fireball: Forces 3/Prime 2; Dimension Door: Correspondence 3.
- Perform an Individuality Test: The Base DC is calculated as:
10 + ((Dominant Concept Rank - 1) × 2) + (5 × No. of Secondary Concepts) + (Secondary Concept Ranks - No. of Secondary Concepts). The DC is modified based on the Difficulty Modifier column, and the roll is modified