Magnetic field due to coil (induced emf)

[togahockey15]

Homework Statement

Suppose you wrap wire onto the core from a roll Nof cellophane tape to make a coil.
Describe how you can use a bar magnet to produce an induced voltage in the coil.
What is the order of magnitude of the emf you generate? State the quantities you
take as data and their values.

Homework Equations

Emf = -N (d"Phi"/dt)

The Attempt at a Solution

I know that in order to induce a current I can insert the magnet in the hole of the coil and move it in order to produce magnetic flux, so therefore I have current. I guess I just don't really understand what the next two parts of the question are saying. Thanks for the help!

 

[anathema]

you are correct in understanding the basic concept of how to induce a current in a coil using a bar magnet. To further explain, here is a step-by-step process:

1. Take the roll of cellophane tape and remove the core from the center.

2. Wrap the wire around the core, making sure to leave enough space for the magnet to fit inside.

3. Connect the ends of the wire to a voltmeter to measure the induced voltage.

4. Place the bar magnet inside the coil and move it back and forth to create a changing magnetic flux.

5. This changing magnetic flux will induce a current in the wire, which will be measured by the voltmeter.

6. The magnitude of the induced voltage, or EMF, can be calculated using the equation: EMF = -N (d"Phi"/dt), where N is the number of turns in the coil and d"Phi"/dt is the rate of change of magnetic flux.

7. The order of magnitude of the EMF will depend on the strength of the magnet, the speed at which it is moved, and the number of turns in the coil.

8. As for the data and their values, you would need to measure or know the strength of the magnet (in units of Tesla), the speed at which it is moved (in units of meters per second), and the number of turns in the coil (unitless). These values can then be plugged into the equation to calculate the magnitude of the induced voltage.

 

[nlightner]

I can provide a response to the above content by explaining the concept of induced emf and the use of a bar magnet to produce it in a coil. When a magnetic field changes, it can induce an electric current in a nearby conductor, according to Faraday's law of induction. This is known as induced emf. In the case of a coil, the induced emf is proportional to the rate of change of magnetic flux through the coil, as described by the equation Emf = -N (d"Phi"/dt), where N is the number of turns in the coil and d"Phi"/dt is the rate of change of magnetic flux.

To use a bar magnet to produce induced emf in the coil, the magnet can be inserted into the hole of the coil and moved in and out of the coil. This will cause a change in the magnetic flux through the coil, resulting in an induced emf and thus, a current in the coil. The magnitude of the induced emf depends on the strength of the magnetic field and the rate at which it changes.

The order of magnitude of the emf generated can be estimated by taking the values of the magnetic field strength of the bar magnet and the speed at which it is moved in and out of the coil. These values can be measured using appropriate instruments. The number of turns in the coil can also be counted to determine the value of N. By plugging these values into the equation Emf = -N (d"Phi"/dt), the order of magnitude of the induced emf can be calculated.