# Alternating Current. (When can we see it?)

• ScienceNerd36
In summary, the conversation discusses the possibility of seeing flickering in a light bulb due to the alternating current passing through it. The concept of persistence of vision is mentioned, along with the factors that affect the visibility of flicker in incandescent lighting. The minimum frequency for flickering is estimated to be around 10 Hz. It is also noted that incandescent bulbs may not easily show flicker due to the temperature of the filament.

#### ScienceNerd36

Hello there my fellow chemical structures!

I was just wondering the other day, while staring vacantly at a lighting fixture: How slow would the AC going back and forth through the light bulb have to be before you could see it flickering?

Any information would be much obliged.

You might want to investigate http://en.wikipedia.org/wiki/Persistence_of_vision" [Broken]. A couple fine points with incandescent lighting: first, the filament will flicker twice for each AC cycle, since resistive heating is independent of current direction. Second, the filament won't go dark instantaneously but will cool down over a time period that depends on the thickness, material, and geometry of the filament. Empirically, I'd expect the minimum frequency to be on the order of 10 Hz, but I don't have a frequency generator handy; perhaps someone else does.

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Thanks

Incandescent bublbs don't easily show flicker because of the temperature of the filament. A flourescent bulb can be seen at 60 Hz.

## 1. What is alternating current?

Alternating current (AC) is a type of electrical current where the direction of the flow of electricity periodically changes. This means that the current alternates between flowing in one direction and then reversing and flowing in the opposite direction.

## 2. How is alternating current different from direct current?

The main difference between alternating current and direct current (DC) is that DC flows in only one direction, while AC alternates between two directions. AC is also typically used for long distance power transmission, while DC is used for smaller electronic devices.

## 3. What are the advantages of using alternating current?

One of the main advantages of AC is that it can be easily transformed to different voltages, making it more efficient for long distance transmission. AC also allows for the use of transformers, which can step up or step down the voltage as needed.

## 4. Can we see alternating current?

No, alternating current itself is not visible. However, AC can power devices such as light bulbs, which produce light that we can see.

## 5. How is alternating current generated?

Alternating current is typically generated by rotating a coil of wire in a magnetic field. This creates a changing magnetic field, which induces an alternating current in the coil. This process is used in power plants to generate electricity for homes and businesses.