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about Light
Our daily lives are filled with a variety light.
For example, natural light which comes from distant stars or the sun, and artificial light such as LED light bulbs and
TV.
We are able to recognize colors and shapes of objectswhen when light enters the eye directly or indirectly.
Light is the same wave phenomenon as waves or waves sound etc.
But "water waves and sound waves" and "light" is different and light also is transmitted in vacuum without mediums.
Vibration is transmitted without the material. This is little difficult to understand. Light is a kind of electromagnetic wave which is transmitted in space as changing electric and magnetic fields. Light is a kind of electromagnetic wave which is transmitted in space of changing electric and magnetic fields.
Light which the human eye feels called
visible light.
Its color varies with the wavelength.
Sunlight is
white light because sunlight contains a variety of wavelengths of light.
Light of one wavelength such as
laser beam is called
monochromatic light.
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LED gotten into the news recently.
| Do you know Light-emitting diode? Now, we can find it in many place. Maybe, you've heard such as long service life, high energy efficiency about it.
First, about lifespan. A LED lamp has lifespan of about 30,000〜50,000 hours. An incandescent lamp's one is about 1,000〜2,000 hours. It is very longer than a incandescent lamp.
Secondly, about electricity usage. A LED lamp electricity usage is 5〜8W. In contrast, an incandescent lamp's one is about 60W. You can understand a LED uses less energy than an incandescent lamp. A LED converts electricity into light directly, so it can emit with efficiency.
However, a LED is more expensive than a previous bulbs.(LED:1000〜1500yen, Previous bulbs:100yen)
LED is evaluated about long service life and high energy efficiency, and used in bulb, illumination, electronic billboards, traffic lights and so on. |
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