Electromagnetism Physics Problems: Get Expert Help with Plainmath

You can feel almost nothing by touching the battery pole of your flashlight with your fingers. When an electric call is connected to the battery, electric punctures are felt with the fingers. Why?

We know that a soft iron bar placed inside a solenoid turns into an electromagnet when current passes through the solenoid. Now my question is how is electricity produced? Is the iron core moved by the turbine inside a solenoid?

Suppose you have two alnico bar magnets, one with a mass of 100 g and one with a mass of a kg. At a distance of a meter from the center of either one, how would the magnetic field differ? Why?

What are the effects of height of wire to magnetism

Let’s say we have two inactive electromagnets spaced one light-minute apart, with north poles pointing toward each other. One of the electromagnets is turned on for ten seconds, and then turned off again (or destroyed). Once the magnetic field from the first electromagnet has propagated to the second, the second electromagnet is turned on. Would the second electromagnet not be repelled away by the magnetic field without exerting a force on the first electromagnet? How is momentum conserved in this scenario?

The magnetic field (in tesla/gauss) of an electromagnet that is very small and has very few windings. For example 12 windings over 0.003 meters. I know this is not going to produce a very strong field, but I would like to pulse a strong current through the coil very briefly to make it stronger. I have found a number of sources listing the formula for the calculation of magnetic field strength
$B=\mathrm{\mu <!--\; \mu \; -->}\mathrm{\rho <!--\; \rho \; -->}I=\mu {\mu }_0\frac{N}{L}I$
where $N$ is the number of turns and $L$ the length of the core, e.g.
Question is
- can this formula be applied to my electromagnet design?
- Does the size and low number of windings on my electromagnet mean this formula is not valid?
- Is there any other way I can calculate/estimate the magnetic field?

A bar magnet with its north pole facing downward is falling toward the center of a horizontal conducting ring. As viewed from above, is the direction of the induced current in the ring clockwise or counterclockwise? Explain.

Heat means stored kinetic energy in matter. Microwave owens and induction heaters works on increasing kinetic energy on matter. Is it possible to make inverse of this heaters like cooler. Can we decrese kinetic energy by using like electromagnetic slower device? It will change many things in engineering.

Does an electromagnet increase in strength more by voltage or wire turns?

How does induced magnetism work with magnetic induction and magnetic domain?

There's a lot of information online about increasing the strength of an electromagnet with more turns, different cores, etc, but not much about factors in the power supply that affect the strength of the magnet.
I've got a commercial electromagnet rated for 12VDC that's supposed to produce 200 lbs of pull. What factors in the power supply will maximize this magnet's strength?

Can a device be constructed of a super conducting disk connected to a electromagnet that generates a field such that the disc locks "in" the field generated by the electromagnet such that the device self levitates without the need for track or permanent magnets?

A wrench 30 cm long lies along the positive y-axis and grips a bolt at the origin. A force is applied in the direction <0, 3, -4>at the end of the wrench. Find the magnitude of the force needed to supply 100 N-m of torque on the bolt.

(a) A car generator turns at 400 rpm when the engine is idling. Its 300-turn, 5.00 by 8.00 cm rectangular coil rotates in an adjustable magnetic field so that it can produce sufficient voltage even at low rpms. What is the field strength needed to produce a 24.0 V peak emf? (b) Discuss how this required field strength compares to those available in permanent and electromagnets.

How could you test the effects of heating and cooling on the magnetization of a bar magnet?

If you wrap an active electric cord around your body, do you become an electromagnet?

An electromagnet was connected to a 12v battery and I verified that it was working. I then touched the electromagnet to a strong regular magnet (rated to hold over 50 kg). There was a strong force between the magnets. I then disconnected the electromagnet from power, reversed the wires, and turned it back on. I expected to feel the electromagnet repel the other magnet, but instead they two magnets got stuck together again. It seems like reversing the wires had no affect on the polarity of the electromagnet.

How are solenoids and electromagnets used in galvanometers, electric motors, and loudspeakers?

A bar magnet falls under the influence of gravity along the axis of a long copper tube. If air resistance is negligible, will there be a force to oppose the descent of the magnet? If so, will the magnet reach a terminal velocity?

What is the correct frame of reference for determining the magnetic force on a charge?
If two charges are both stationary in a given inertial frame, F1, then neither charge should experience a magnetic force due to the presence of the other charge (qv = 0). If we accelerate one charge, but not the other, then again, neither charge should experience a magnetic force, since only one charge has a non-zero velocity as measured in that inertial frame, meaning the other, stationary charge will experience no force in the magnetic field of the moving charge.
Now imagine that we are riding along as part of another inertial frame, F2, and that the first inertial frame discussed above that contains the two electrons F1, is traveling at a relative velocity of v from our perspective (i.e., it’s moving faster than us). Now imagine that we fire two electrons from our inertial frame F2, towards F1, one that travels at a velocity of v from our perspective, thereby traveling at the same velocity as the electron that appeared stationary in F1, and another that travels at the same velocity as the second, "faster" electron.
From our perspective in F2, both electrons have a non-zero velocity: the “slow one” traveling at a velocity of v, and the “fast one” traveling a bit faster than that. From our perspective, in F2, both electrons should experience a magnetic force of attraction due to their non-zero velocities in non-zero magnetic fields, which would change the path of those electrons from the perspective of both inertial frames.
However, from the perspective of F1, the “slow” electron is stationary, and should not experience any magnetic force in any magnetic field.
This seems to not make sense - what would happen as an experimental matter?