Power & Magnetism: Calculating Resistance & Loss

In summary, when a magnet passes through a solenoid, it induces a DC voltage in the wire. To calculate the power, we use Ohm's law and P=VI. While there is power loss due to resistance, the opposing magnetic field caused by Lenz's law does not contribute to this loss. When a magnet moves through a stationary coil, it induces an AC voltage, seen as a one half sine wave on an oscilloscope. As the magnet is pushed back and forth at a fixed speed, the back EMF created by the induced current makes it harder to push and requires a greater force, resulting in a greater current. This does not cause a loss of power, but instead is necessary to conserve energy. Without
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If we have a solenoid and a magnetic passes through it , it will produce a dc voltage in the wire . If we want to calculate the power , we find out the current using ohms law then we use P=VI . I know there is power loss due to the resistance ( joule effect) . But what about the opposing magnetic field due to current in the wires (lenz's law) , does it contribute in the power loss ?
 
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if you have a stationary coil and a magnet " MOVING" through that coil you don't get dc but AC.
If you would look at an oscilloscope you would see a one half of a sine wave.
If you would continue to push the magnet back and forth at a fixed speed you would get a sine wave output.

The back EMF due to the induced current it pushes against the magnet so to speak so it will get harder for you to push that magnet through.
The faster you will try to push the magnet the harder it will become to do that.You will need to supply a greater force to the magnet which will equal in greater current induced.
 
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There really isn't a loss of power. The amount of power required to push the magnet through will be equal to the total amount of power generated in the coil. However, due to the resistance of the wire, some of the power will be used to heat the wire instead of performing useful work. The opposing magnetic field doesn't cause a loss of power. Instead it is a requirement in order to conserve energy. Without the opposing magnetic field it wouldn't require any work to move the magnet through the coil and you would be creating energy from nothing.
 
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1. What is resistance and how is it calculated in a circuit?

Resistance is the measure of how much a material or component impedes the flow of electricity in a circuit. It is calculated using Ohm's law, which states that resistance (R) is equal to the voltage (V) divided by the current (I), or R = V/I.

2. How do you calculate the power in a circuit?

Power is the rate at which energy is transferred or converted, and it is measured in watts (W). In a circuit, power can be calculated using the equation P = V x I, where V is the voltage and I is the current.

3. What is the relationship between resistance and power loss in a circuit?

The higher the resistance in a circuit, the higher the power loss. This is because as resistance increases, more energy is converted into heat, resulting in a loss of power.

4. How does magnetism affect power in a circuit?

Magnetism does not directly affect power in a circuit. However, it can induce an electric current in a nearby conductor, which can affect the power in that circuit. This is known as electromagnetic induction.

5. What factors can affect resistance and power loss in a circuit?

Resistance and power loss in a circuit can be affected by the material and thickness of the conductors, the temperature of the circuit, and the length and cross-sectional area of the circuit. Other factors such as the presence of magnetic fields and the type of circuit components can also impact resistance and power loss.

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