Tuesday, May 18, 2010
-a closed path in which to conduct energy (so that there is a path for electrons to flow)
Examples of DC circuits:
Parallel Circuit-In a parallel circuit each resistor provides a new path for electrons so the total current is equal to the sum of the currents through each resistor. Because the elenments are in parallel, the volotage drop is also equal to the total voltage of the source. As you can see the voltage of one of the lightbulbs is equal to the voltage of the battery and the sum of the current is equal to the total current.
Combo Circuit-a combo circuit is a circuit that includes both parallel and series elements and the current in a complex circuit can be found by calculating the sum of the resistence in the parallel elements and adding it to the resistance of the series elements. Then you can use that resistence and the voltage of the battery to determine the current. The rules for the current of series and parallel circuits both apply, in all the series elements the current is the same and the sum of the current of the parallel elements is equal to the total parallel resistence. The same rules as previous circuits also apply to the voltage, the voltage drop of each parallel element is equal to the sum of the voltage in the entire parallel part of the cicruit. for the series part, the voltage for each series elements is equal to the total voltage for the entire series part of the circuit. as seen in the picture below the sum of the amperage in the parallel is equal to the total amerage and also the amperage in the series.the voltage of the series if added to the voltage of the parallel elements will equal the total voltage.
Saturday, May 1, 2010
What you are seeing in the picture above is a prime example of wave interference. Wave interference is, simply put, what happens when waves traveling in the same medium meet. There are two types of wave interference, constructive interference and destructive interference. Constructive interference occurs when two waves in the same medium tih displacement in the same direction (from the normal) meet. In constructive interference waves can have either a positive or negative displacement from the normal, as long as it is in the same direction. Interference of the Destructive variety occurs when two waves in the same medium that have opposite directions of displacement meet. In the picture above, you can see as the water leaves the Jacuzzi and enters the swimming pool the water makes a series of circular waves when it enters. The waves undergo interference and create the patters seen in the picture. There are both waves crests and troughs and at different point in small disturbances in the water where wave interference between them is occurring. The way the water moves into the pool is an exemplary example of another idea of physics as well. As you gaze down at the bottom of the pool you may realize that the water is casting shadows, but how can water cast shadows if it is transparent? The answer lies in the make up of water itself. Although water is clear it does not let all light pass through it, only 98% of incident light is transmitted through the water. The 2% decrease of light is the reason that the shadows appear.