Expert Electromagnetism Example Problems and Physics Help

High School
Physics
Electromagnetism

Does protons moving parallel to each other exert magnetic force?
If two protons are moving parallel to each other in same direction with equal velocities then do they exert magnetic force on each other.? As protons are moving they should produce magnetic field and there should be some magnetic force + electric force on each of them. But if look from their refrence frame then both the protons are at rest and hence there will be no magnetic force (as magnetic field is created by a moving charge), only electric force on each of them. How can this be possible that force(magnetic force) on a particle becomes different on changing the reference frame even though the reference frames are non accelerating with respect to each other?

robinmarian9nhn8 2022-04-12

Consider the circuit shown in
photo
A)What are the magnitude and direction of the current in the $20 Ω$
resistor in figure
Express your answer with the appropriate units. Enter positive value if the current is clockwise and negative value if the current is counterclockwise.

Matilda Webb 2022-04-12

The Maxwell equation $\oint \vec{E} \cdot \vec{d A} = - \frac{Q_{i n}}{ϵ_{0}}$ is also called
a. Faraday's Law of Electromagnetic induction
b. Ampere's Law
c. Gauss Law of Magnetism
d. Gauss Law of Electricity

tiyakexdw4 2022-04-12

Work done by magnetic force
By Lorentz force law, $F_{m}$ is always perpendicular to velocity of charge $v$ . But $F_{m}$ is not necessarily perpendicular to the displacement of charge caused by $F_{m}$
Then how can we say that magnetic force does no work?
Edit:
One thing to clear: Is work done = displacement just before the force was applied dotted with force OR displacement just after the force was applied dotted with force? If the former were true, you would be correct. But if the latter were true, I don't see any reason why $F_{m}$ is perpendicular to the displacement just after the force was applied as there should be a component of displacement in the direction of force.

Yasmine Larson 2022-04-12

If a ferromagnetic material is immersed in an alternating magnetic field at frequency $ω$ , the material will follow a hysteresis cycle at that frequency. But if that frequency is high enough, the spins will oscillate more and more, and I think it will somehow increase the temperature of the material (because in a classical picture: more frequency $\Rightarrow$ more velocity $\Rightarrow$ more kinetic energy $\Rightarrow$ more temperature.)
As hysteresis only appear below the Curie temperature, if higher frequencies make the metal get hotter, there will be a critical frequency $ω_{c}$ , above which hysteresis won't appear. Does such frequency exists for every ferromagnetic material?

Jazlyn Raymond 2022-04-12

Consider a region where a 35-volt-per-meter electric field and a 20-millitesla magnetic field both exists and are perpendicular to each other. If a proton is moving at a speed of 2 km/s and the magnitude of the force it experiences is $8 \times 10^{- 18}$ newtons, determine the direction of the movement of the proton relative to the direction lying on the same plane. the magnetic field. Assume the electric field, magnetic field, and the velocity vector are all
a.) 47.13 degrees with respect to the magnetic field;
b.) 63.21 degrees with respect to the magnetic field;
c.) 87.20 degrees with respect to the magnetic field;
d.) 21.90 degrees with respect to the magnetic field;

hovudverkocym6 2022-04-12

The Maxwell equation derived from Gauss's Law in magnetism is
$a) \oint \vec{E} . \vec{d s} = - \frac{d Φ_{m}}{d t} b) \oint \vec{B} . \vec{d s} = μ_{0} I + ϵ_{0} μ_{0} \frac{d Φ_{E}}{d t} c) \oint \vec{E} . \vec{d A} = \frac{Q_{i n}}{ϵ_{0}} d) \oint \vec{B} . \vec{d A} = 0$

Alaina Holt 2022-04-12

Manganese has five unpaired electrons, but Iron has four, then why is Iron ferromagnetic and Manganese paramagnetic? What's that property I'm missing?

tuehanhyd8ml 2022-04-07

I understand that the magnetization must saturate as more and more domains are aligned. But B is still directly proportional to H, and hence it must increase linearly with H. But every book that teaches B−H curve, says that it saturates after some time. How can this be so?

Damion Hardin 2022-04-07

Is Magnetic force different in different frames?
Suppose a charged particle moves with a velocity $v$ near a wire carrying an electric current. So, a magnetic force acts on it. If the same particle is seen from a frame moving with velocity $v$ in the same direction, the charge will be found to be at rest. Will the magnetic force become zero in this frame? Will the magnetic field become zero in this frame?
Even though the solution says that the force shall be zero but the magnetic field will be independent of frame and henceforth exist, I am not convinced with the idea of zero force because even if I were to place myself in a frame moving with velocity $v$ , I will see the particle executing a circular motion around a different center though. In reality I know that its the magnetic force that's causing it to move in a circle but in my frame if I say that there is no magnetic force, how would I explain the circular motion of the particle ?

lasquiyas5loaa 2022-04-07

How Can There Be Magnetic Force Without Velocity
Suppose there is a space with constant magnetic field, and a charged particle is moving in that space with a constant velocity, ofcourse it experiences a magnetic force and gets deflected.
But the particle it not necessarily moving wrt all frames. There may be some frame for which the particle doesn't move at all but still gets deflected. How is this possible, there must be some velocity for the particle to experience any deflection under influence of a magnetic field?
Also a still particle in the same space doesn't experience any deflection. True, but the same particle may be moving wrt to some other frame without experiencing a magnetic force, so here we have a velocity but no magnetic force case.
I remember I have used the relation $| F | = q v | B |$ a lot before, but I am afraid to use it any more, these things are really confusing.

Alisa Durham 2022-04-06

I'm trying to learn the connection between special relativity and magnetism. I know that if I place a positive charge, at rest, next to wire with current, I should not observe any force on it because there is no electric field and there is no magnetic force as my charge is at rest.
But here is what confuses me - the wire contains moving electrons and according to what I learned, the stationary charge should observe a length contraction of those electrons and so the density of them will increase and a negative electric field should be observed.
This is definitely not the case and I wonder if someone can explain to me what is wrong in my analysts.

poklanima5lqp3 2022-04-06

A cubical box 22 cm on a side is placed in a uniform 0.35-T magnetic field. Find the net magnetic flux through the box

Regina Ewing 2022-04-06

Mysterious magnetic force!
If you have a loop in which current goes clockwise as seen from top, then it forms a north pole if seen from below. Now if a particle with positive charge goes from left to right under it, it experiences and upward force, now if the 1st loop was very large and particle goes from near about the axis of loop, it goes in a circle in anti-clockwise direction as seen from the top. This again generates a north pole if seen from top.
Q1. Since we have two north poles facing each other, why don't we get a new repulsive magnetic force?
If you closely observe this systen then the negative charges travelling in 1st loop in anti-clockwise direction have synchronized with the positive charge going anti-clockwise below it. Not only this, if you send the particle from right to left, it experiences a downward force and again synchronizes, now again if you try sending negative particles they get synchronized in the same way with the positive particles.
Q2. Why is such a synchronizing taking place?
I am more interested in the first question for now, as I am trying to work out the second problem myself.

hisyhauttaq84w 2022-04-06

What is the magnitude of the net force on the first wire in (Figure 1)?
What is the magnitude of the net force on the second wire in (Figure 1)?
What is the magnitude of the net force on the third wire in (Figure 1)?
photo

junoonib89p4 2022-04-06

Electric force vs. Magnetic force
$E$ , electric field $\to$ $H$ , magnetic field
$D$ , electric flux density $\to$ $B$ , magnetic flux density
$D = ϵ E$ $\to$ $B = μ H$
Electric force calculation is based on electric field: $F = q E$
But...
Magnetic force calculation is based on not magnetic field( $H$ ) but magnetic flux density( $B$ ):
$F = q v \times B$
What is the reason behind that? For magnetic force, why is magnetic flux density is used instead of magnetic field?

tripiverded9 2022-01-15

A very long, uniformly charged cylinder has radius R and linear charge density $λ$ .
a. Find the cylinder's electric field strength outside the cylinder, $r \geq R$ . Give your answer as a multiple of $\frac{λ}{ξ_{0}}$ .
Express your answer in terms of some or all of the variables R, r, and the constant $π$ .
b. Find the cylinder's electric field strength inside the cylinder, $r \leq R$ . Give your answer as a multiple of $\frac{λ}{ξ_{0}}$ .
Express your answer in terms of some or all of the variables R, r, and the constant $π$ .

aspifsGak5u 2022-01-11

Along coaxial cable consists of an inner cylindrical conductor with radius a and an outer coaxial cylinder with inner radius b and outer radius c. The outer cylinder is mounted on insulating supports and has no net charge. The inner cylinder has a uniform positive charge per unit length $λ$ . Calculate the electric field
a) at any point between the cylinders a distance r from the axis and
b) at any point outside the outer cylinder.
c) Graph the magnitude of the electric field as a function of the distance r from the axis of the cable, from r= 0 to r= 2c.
d) Find the charge per unit length on the inner surface and on the outer surface of the outer cylinder.

kdgg0909gn 2021-11-16

Boxes A and B are in contact on a horizontal, frictionless surface. Box A has mass 20.0 kg and box B has mass 5.0 kg. A horizontal force of 250 N is exerted on box A. What is the magnitude of the force that box A exerts on box B?

Maggenifh 2021-11-10

The diffuser in a jet engine is designed to decrease the kinetic energy of the air entering the engine compressor without any work or heat interactions. Calculate the velocity at the exit of a diffuser when air at 100 kPa and $30^{\circ} {$ C enters it with a velocity of 350 m/s and the exit state is 200 kPa and $90^{\circ} {C .$

Electromagnetism Physics belongs to those aspects of the science that can be applied to anything from engineering to design and construction of automation for our daily life. Since we are dealing with the relations between electricity and magnetism, finding answers and questions that we present will help you to see practical examples like radio, gamma rays, or microwave emissions. Take at least one electromagnetism example and you will be able to repeat the steps or receive relevant help. Make sure to focus on the experiments and the order of the steps to gain even more clarity as you study electromagnetism.

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