Understanding the Concepts
* Luminous Flux (Φ): The total amount of light emitted by a source, measured in lumens (lm).
* Illuminance (E): The amount of light falling on a surface, measured in lux (lx). One lux is equal to one lumen per square meter (lm/m²).
Formula
The relationship between luminous flux (Φ), illuminance (E), and the area (A) of the illuminated surface is:
E = Φ / A
Calculating the Area
We need to know the area of the table to calculate the illuminance. Let's assume the table is circular with a radius of 1 meter.
* Area of a circle: A = πr²
* A = π * (1 m)² = π m²
Calculating Illuminance
Now we can calculate the illuminance:
* E = Φ / A
* E = 1275 lm / π m²
* E ≈ 406.4 lx
Therefore, the illuminance on the table is approximately 406.4 lux.
Important Note: This calculation assumes the light source is a point source and that the light falls directly and uniformly on the table. In reality, light sources have different shapes and spread, and light can be reflected and absorbed by surfaces, affecting the actual illuminance.
