klepkowy7c

2022-07-21

If an ideal cylindrical inductor/electromagnet is charged and then discharged, will the energy lost by charging the inductor/electromagnet be equal to the energy gained by discharging it or will some of it be lost to radiation? Based on what I know about magnetism, there should be no loss.

tiltat9h

Beginner2022-07-22Added 14 answers

An ideal inductor is lossless, so by definition it does not radiate. But an ideal inductor exists only in circuit theory, not in reality.

A real inductor does radiate. We know this because it can cause interference with other circuits nearby. Shielded inductors are available, designed to minimize this effect.

However, in terms of the power lost from the inductor itself, the radiation losses are typically much smaller than the resistive losses due to the imperfect conductivity of the wire used to form the inductor.

Furthermore, radiation increases when the associated wavelength of the signals in the circuit become short enough to be comparable to the physical dimensions of the circuit. But inductors have other limitations (inter-winding capacitance) that limit their usability at high frequencies (with short corresponding wavelengths).

Therefore you almost never have to account for radiation losses from inductors in circuit design.

Also, it is possible to make a loop antenna which is essentially an inductor chosen to maximize its radiation in some frequency band. Typically these are used for receiving rather than transmitting, but reciprocity tells us that the transmitting and receiving behaviors are equal.

A real inductor does radiate. We know this because it can cause interference with other circuits nearby. Shielded inductors are available, designed to minimize this effect.

However, in terms of the power lost from the inductor itself, the radiation losses are typically much smaller than the resistive losses due to the imperfect conductivity of the wire used to form the inductor.

Furthermore, radiation increases when the associated wavelength of the signals in the circuit become short enough to be comparable to the physical dimensions of the circuit. But inductors have other limitations (inter-winding capacitance) that limit their usability at high frequencies (with short corresponding wavelengths).

Therefore you almost never have to account for radiation losses from inductors in circuit design.

Also, it is possible to make a loop antenna which is essentially an inductor chosen to maximize its radiation in some frequency band. Typically these are used for receiving rather than transmitting, but reciprocity tells us that the transmitting and receiving behaviors are equal.

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 $f\left(x\right)=5x-{x}^{2}$?