klepkowy7c

2022-07-21

Electrons' Motion in an electromagnet is on the order of ${10}^{-4}$ m/s. That charge can be mechanically rotated in a capacitor with a million times more velocity (B produced being proportional to charge's velocity ).

Forces causing eddy currents would help to negate net magnetic field in an ordinary capacitor. However, if radially oriented, unidirectionally conducting (" chair " ) carbon nanotubes are rotated, the electrons would be relatively constrained from eddy currents.

It seems like this would allow greater magnetic field production compared to standard electromagnets.

Forces causing eddy currents would help to negate net magnetic field in an ordinary capacitor. However, if radially oriented, unidirectionally conducting (" chair " ) carbon nanotubes are rotated, the electrons would be relatively constrained from eddy currents.

It seems like this would allow greater magnetic field production compared to standard electromagnets.

uavklarajo

Beginner2022-07-22Added 17 answers

Say we have a little electromagnet maybe $5$ cm long with $100$ loops of wire and we run $0.25$ A of current through it. With an air core we should get a magnetic field inside or about $1$ millitesla.

Now, what if we wanted to do that with a rotating static charge? You are proposing moving it a million times faster than ${10}^{-4}$ m/s so $100$ m/s.

In our solenoid we are using the same current $100$ times to produce the magnetic field, effectively it's like a $25$ A current going around a loop once. We need to get the equivalent of a $25$ amp current by swinging some charges around. Current is the rate of charge flow, $I=q/\mathrm{\Delta}t$, so we need to estimate $\mathrm{\Delta}t$ which will depend on the radius or rotation - let's say, arbitrarily, 1 cm. So, $\mathrm{\Delta}d\simeq 6$ cm which gives $\mathrm{\Delta}t\simeq 6\times {10}^{-4}$ s. And, when we solve for q we get $0.015$ coulombs. This is not a small amount of static charge to produce a modest magnetic field. (Remember those van de Graaff generators from physics class that made your hair stand up - that had a charge in the order of $0.000005\text{}C.$) And that, I think, is where your problem is going to be.

Now, what if we wanted to do that with a rotating static charge? You are proposing moving it a million times faster than ${10}^{-4}$ m/s so $100$ m/s.

In our solenoid we are using the same current $100$ times to produce the magnetic field, effectively it's like a $25$ A current going around a loop once. We need to get the equivalent of a $25$ amp current by swinging some charges around. Current is the rate of charge flow, $I=q/\mathrm{\Delta}t$, so we need to estimate $\mathrm{\Delta}t$ which will depend on the radius or rotation - let's say, arbitrarily, 1 cm. So, $\mathrm{\Delta}d\simeq 6$ cm which gives $\mathrm{\Delta}t\simeq 6\times {10}^{-4}$ s. And, when we solve for q we get $0.015$ coulombs. This is not a small amount of static charge to produce a modest magnetic field. (Remember those van de Graaff generators from physics class that made your hair stand up - that had a charge in the order of $0.000005\text{}C.$) And that, I think, is where your problem is going to be.

The magnetic field inside a long straight solenoid carrying current

A)is zero

B)increases along its radius

C)increases as we move towards its ends

D)is the same at all pointsWhich of the following units is used to express frequency?

Hertz

Watt

Newton

PascalWhat does tangential force produce?

How Many Different $f$ Orbitals Are There?

What is $\frac{e}{m}$ value for electrons ?

Which of the following correctly describes the magnetic field near a long straight wire?

A. The field consists of straight lines perpendicular to the wire

B. The field consists of straight lines parallel to the wire

C. The field consists of radial lines originating from the wire

D. The field consists of concentric circles centered on the wireIs energy directly proportional to frequency?

What is a compass? How is a compass used to find directions?

Magnetic field lines never intersect each other because

There will be two directions of the field at the same point.

Feild lines repel each other

Field lines follow discrete paths only

If field lines intersect they create a new magnetic field within the existing fieldTwo parallel wires carry currents of 20 A and 40 A in opposite directions. Another wire carrying a current antiparallel to 20 A is placed midway between the two wires. The magnetic force on it will be

Towards 20 A

Towards 40 A

Zero

Perpendicular to the plane of the currentWhat is the wavelength of the light emitted when an electron in a hydrogen atom undergoes transition from the energy level n = 4 to energy level n = 2? What is the colour corresponding to their wavelengths? (Given ${R}_{H}=109677c{m}^{-1}$)

A) 486 nm, Blue

B) 576 nm, Blue

C) 650, Blue

D) 450 nm, BlueTwo identical conducting spheres A and B are separated by a distance greater than their diameters the spheres carry equal charges and electrostatic force between them is F a third identical uncharged sphere C is first brought in contact with A, then with B and finally removed as a result, the electrostatic force between A and B becomes

Why is alternating current used in homes?

Which of the following radiation has the shortest wavelength.

X-ray

Infra red

microwave

ultravioletHow to find the local extrema for $f\left(x\right)=5x-{x}^{2}$?