5 Factors to Consider when buying an Energy Efficient Light Bulb
- Wattage. Wattage is a measurement of the amount of energy consumed by the light bulb.
- Lumens. The light output of a lamp is measured in lumens.
- Base. At the very bottom of the bulb, you have the base.
- Color Temperature.
- MOL.
There are three basic types of lighting you should layer in a room in order to accomplish this:
- Ambient or general lighting.
- Accent lighting.
- Task lighting.
Types of illumination
- Halogen incandescent lamps.
- LED illumination.
- Fluorescent light (high frequency)
- Metal halide light sources (as "cold light" sources with fibre optic transmission)
- Xenon strobe lamps and metal halide lamps are used quite rarely in industrial machine vision.
Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface and the direction of the incident wave.
The quantity of light that illuminates a surface; measured in foot candles or in lux.
What are the criteria of a good lighting?
- light intensity,
- uniformity of light,
- dazzle capability and luminance distribution,
- light pulsation and colour rendering,
- shading of light.
Our ability to perform a visual task depends on how well our eyes perceive the details of the task. Factors determining the visibility of task details include size, luminance, contrast and glare. These factors are interrelated. Size: Making objects larger, or moving them closer to our eyes, makes them easier to see.
Illuminance is the metric that is used to measure the light intensity within a space. Therefore, light intensity is measured in terms of lumens per square foot (footcandles) or lumens per square meter (lux).
Wavelength is a major factor that affects the intensity of color. Larger absorbency will occur between two colors that have the greatest change in wavelength. For example, if a dye and light color were the same, the percent transmittance would be large. Concentration is also a factor affecting color intensity.
The factors affecting the intensity of light are diffraction. Light has three properties: Wavelength, speed, and amplitude. The wavelength determines the type of light (color, etc.). Speed is determined by whether light passes through a vacuum or some material.
The intensity varies with the distance from the source and the power of the source. Power is a property of the light source that describes the rate at which light energy is emitted by the source. Power is often expressed in units of watts. Different light bulbs are rated to have different power values.
Several factors can affect the rate of photosynthesis:
light intensity.
carbon dioxide concentration.
temperature.
Factors affecting photosynthesis
- the rate of oxygen output.
- the rate of carbon dioxide uptake.
- the rate of carbohydrate (glucose) production.
Iris Diaphragm: A rotating disc under the stage that controls the intensity of light hitting the specimen. Illuminator: The light source, which illuminates the specimen.
So in the case of a plant, a higher light intensity means more packets of light called “photons” are hitting the leaves. As you rise from low light intensity to higher light intensity, the rate of photosynthesis will increase because there is more light available to drive the reactions of photosynthesis.
Some factors that affect intensity are the distance away from the epicenter, the depth of the earthquake, the population density of the area affected by the earthquake, the local geology of the are, the type of building construction in the area, and the duration of the shaking.
The main factors affecting rate of photosynthesis are light intensity, carbon dioxide concentration and temperature.
The intensity or brightness of light as a function of the distance from the light source follows an inverse square relationship. The decrease goes as r squared because the area over which the light is spread is proportional to the distance squared.
Architects often
use a combination of these strategies to maximize
natural light in a space.
Here are a few design elements that architects use to bring in as much natural daylight as possible:
- Building orientation.
- Windows.
- Skylights.
- Clerestories.
- External Shading Systems.
- Light shelves.
- Solar tubes.
Exposure to natural light helps our bodies produce Vitamin D, improves our circadian rhythms and sleep patterns, helps us to focus, enables us to get more done, and even makes us happier. Ensuring we get enough of this vital resource is key to our physical and psychological wellbeing.
Science has shown that simply being exposed to natural light for a short period of time can prevent depression in adults as well as children and boost one's spirits and reduce stress levels. The use of natural light in a home or business space is cleaner for all inhabitants and also helps preserve the environment.
Natural sources of light include the sun, stars, fire, and electricity in storms. There are even some animals and plants that can create their own light, such as fireflies, jellyfish, and mushrooms. This is called bioluminescence.
Natural light is the light generated naturally. The most common source of natural light on Earth is the Sun. Artificial light is generated by artificial sources, such as incandescent lamps, compact fluorescent lamps (CFLs), LEDs, etc.
It bounces sunlight toward the camera's subject and makes sure they're always more lit from the front than from the back. This is what allows photographers to produced detailed, high contrast photos of their subjects.
Daylighting is the practice of placing windows, skylights, other openings, and reflective surfaces so that sunlight (direct or indirect) can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use.
: the light from the sun : sunlight indoor photographs made in natural light.
Passive lighting is any architectural element that uses sunlight to light interiors without using electronics such as solar panels. This includes both techniques perfected before the invention of electric light and approaches that make use of modern materials and design knowledge.
Kitchens achieve a minimum daylight factor of at least 2%; living rooms, dining rooms and studies achieve a minimum average daylight factor of at least 1.5%, and 80% of the working plane should receive direct light from the sky”.
With fingers together, place the bottom of your pinky on the horizon line. You need to measure how many fingers can fit between the horizon and the bottom of the sun. Four fingers equals one hour, with each finger representing 15 minutes.
For Natural LightSo, if a room is 10 feet wide x 12 feet long, then the room area would be 120 square feet and the minimum size of the window in that room would have to be12 square feet. A three foot by four foot window would provide 12 square feet of natural light to the room – again, the required minimum.
To identify the ideal middle ground, designers use a variety of approaches. One of the most common is the average daylight factor (ADF). Simply put, a daylight factor is how the level of light inside a building compares to the level of light outside a building.
For example: For a 20m2 room the minimum area required for natural light is 10%. If a rooflight is installed only 0.6m2 would be required. If the roof light was only 0.3m2, then a window or equivalent borrowed light would be necessary. This would need to be an additional 1.0m2.
3 Vertical sky component (VSC) is a 'spot' measure of the skylight reaching the mid-point of a window from an overcast sky. It represents the amount of visible sky that can be seen from that reference point, from over and around an obstruction in front of the window.
The amount of daylight received in an internal space can be analyzed by measuring illuminance on a grid or undertaking a daylight factor calculation. Computer programs such as Radiance allow an architect or engineer to quickly calculate benefits of a particular design. The source of all daylight is the Sun.
What is glare? Glare is the loss of visual performance or discomfort produced by an intensity of light in the visual field greater than the intensity of light to which the eyes are adapted. Simply put, glare occurs when too much light enters your eye and interferes with your eye's ability to manage it.
Their study suggested high reflectance values between 70% and 80% for ceilings and reflection coefficient above 50% for walls in order to maximize the distribution of daylight in the area.
