1. Given The Magnetic Field 202 A/m: Test

Magnetic field strength is defined as the magnetomotive forceper unit length, and its SI unit of measurement is theampere per metre (usually spoken as 'ampere-turn permetre').

CURRENT BALANCE OBJECTIVE To use the current balance to measure the mechanical forces exerted by electrical currents. INTRODUCTION If a current I passes through an infinitely long straight wire, the resultant magnetic field produced outside the wire is given by d I B S P 0 2, (1) where d is the radial distance from the center of the wire and P 0. So far we have described the magnitude of the magnetic force on a moving electric charge, but not the direction. The magnetic field is a vector field, thus the force applied will be oriented in a particular direction. There is a clever way to determine this direction using nothing more than your right hand.

What is the unit used to measure the strength of a magnetic field?

It depends on what you mean by 'the strength of a magnetic field'. If you mean 'magnetic flux', then the SI unit is the weber (pronounced 'vay-ber'). If you mean 'magnetic flux density', then the SI unit is the tesla. If you mean 'magnetic field strength', then the SI unit is the ampere per metre.

What is the unit of magnetic field?

the unit of magnetic field is tesla (si unit ) and gauss (cgs ) unit. 1 tesla = 10,000 gauss . 1 tesla= 1N/mA Answer It depends on what you mean by 'magnetic field'. If you mean 'magnetic flux', then the SI unit is the weber (pronounced 'vay-ber'). If you mean 'magnetic flux density', then the SI unit is the tesla. If you mean 'magnetic field strength', then the SI unit is the ampere per… Read More

Magnetic field strength unit?

Oersted which is equal to 79.58 Am-1 Answer An oersted is an obsolete (cgsA) unit of measurement for flux density, not magnetic field strength. The SI unit is the ampere per metre.

What Magnetic field strengthcalled?

In the SI system magnetic field strength is measured in Teslas, and 1 Tesla = 1 Weber/m2. These SI units replace the previously used units Gauss and Maxwell, with 1 Tesla = 104 gauss, and 1 Weber = 108 Maxwell. the subunits of the Weber are Volts x seconds, so the Tesla is ( Volts x Seconds)/m2. Further insight can be obtained from the relation Change of flux of 1 weber/sec produces an EMF of… Read More

What is the formula for calculating magnetic field strength?

'Magnetic field strength' (symbol: H) is defined as 'the magnetomotive force, per unit length, of a magnetic circuit'. In SI, it is expressed in amperes per metre (A/m), which is often spoken as 'ampere turns' per metre'. It's equation is: H = (IN) / l where: H = magnetic field strength (ampere per metre) I = current flowing through coil (amperes) N = number of turns in coil l = length of magnetic circuit

How strong is earths magnetic field?

Magnetic Field Strengths are often measured in the unit 'gauss' ( the SI unit is the 'tesla'). The strength of the Earth's Magnetic Field, measured at its core, is 25 gauss. More useful probably is the strength of the field at the surface of the Earth. This varies from place to place. Also, it seems to have become weaker over recent centuries. The strength at the surface is about 0.3 to 0.6 gauss. (For comparison… Read More

How does magnetic field strength relate to the closeness of magnetic field lines about a bar magnet?

Magnetic field strength (H) is defined as the magnetomotive force per unit length, and is expressed in amperes per metre (often spoken as 'ampere turns per metre') in SI. An older, and far more descriptive term, is 'magnetomotive force gradient'. The 'closeness' or intensity of a magnetic field's flux lines, on the other hand is termed magnetic flux density (B), expressed in teslas in SI. There is a complex relationship between magnetic field strength and… Read More

What is the interactions between electricity and magnetism?

The main one is that electric current, which consists of electric charges flowing along a wire, sets up a magnetic field around the wire. The field lines are circles, with the magnetic field at right-angles to the current. The magnetic field intensity at distance r from the wire is given in SI units by: H = i/(2.pi.r) The second is magnetic induction, in which a voltage is induced in a loop of wire if the… Read More

What is the weight on earth of an object with a mass of 100g?

Convert that to kilograms, then multiply the result by the strength of the gravitational field (about 9.8 in SI units). Answer will be in newton.

What is the unit for magnetic force?

The SI unit for force is the newton, N = kg m s-2. Magnetic field strength is measured in tesla, T = V s m-2 (or N A-1 m-1, or kg A-1 s-2, etc.). The strength of Earth's magnetic field is about 3 x 10-5 T.

What is magnetic flux measured in?

The SI unit of magnetic flux is the weber (in derived units: volt-seconds)

What is Magnetic flux density unit?

'Magnetic flux density' is also known as the magnetic field, The SI unit for this is the Tesla, written as T. Comment Magnetic flux density is not 'also known as the magnetic field'. It describes the intensity of a magnetic field.

What is 40mT mean in magenetic fields?

40mT means 40 milli Tesla. A Tesla is a derived unit in the SI system of measures, and is a measure of magnetic field strength. The quantity given is rather small, but would be equal to that of a handful of fridge magnets. The Earth's magnetic field is about 30 micro Tesla.

What is the SI unit for strength?

If you mean force, the SI unit is the newton. If you mean the strength of a material - its ability to withstand force - there are different types of strength: look up Compressive strength, Tensile strength, Shear strength. For example, the units for tensile strength are newtons / square meter.

What is the SI derived unit?

A derived SI unit is made up of two or more SI base units. There are dozens of them. Pressure, volume, area, force, acceleration, velocity, energy, torque, momentum, power, temperature, electric and magnetic field, electric and magnetic flux, capacitance, inductance, eclectic potential, resistance, pressure, density, molar mass, and frequency are all derived SI values.

What is the sl unit for magnetic field?

There are several ways of defining a magnetic field and these depend on the effect that the field has on its environment. The B-field (also called the magnetic flux density) is measured in teslas. The H-field (also called the magnetic flux intensity) is measured in newtons per metre per ampere.

What two variables are multiplied together to calculate weight?

weight = mass x gravityGravity refers to the strength of the gravitational field, which (in SI units) is expressed in newton / kilogram, or the equivalent, meters / second squared.

How are SI units used in the US?

SI units are used mostly in the scientific field in the US. Almost every country in the world use them for everyday measurements, but the US uses the US Customary System. Using the SI units in the scientific field makes it possible for scientists to share information without having to convert the measurements.SI units are used mostly in the scientific field in the US. Almost every country in the world use them for everyday measurements.

What is magnetomotive force per unit length?

Magnetomotive force per unit length is the definition of magnetic field strength (symbol: H), formerly known as 'magnetising force'. Magnetomotive force is the product the the current flowing through a coil and the number of turns that make up that coil, and its SI unit of measurement is the ampere (although this is often spoken as 'ampere turn'). So, the SI unit of measurement of magnetic field strength is the ampere per metre, although, again… Read More

What is the universal system of units among scientists?

It is a system of units that deleted the confusion in the SI system of units. According to many scientists; there are some redundancies in the SI system of units. Through an entropy approach that depends on a previous analogy between the electrical, mechanical and thermal fields; it was possible to introduce an approach to a system of units that removes such redundancies. According to the second law of thermodynamics; the temperature was defined as… Read More

What does the SI in SI units stand for?

SI in SI units stand for SYSTEM INTERNATIONAL Units has two units 1. Base unit 2. Derived unit

What is the unit of dielectric strength?

In SI, the unit of dielectric strength is volts per meter (V/m). In U.S. customary units, dielectric strength is often specified in volts per mil. In physics, dielectric strength 2 meanings: Of an insulating material, the maximum electric field that a pure material can withstand under ideal conditions without breaking down. For a specific configuration of dielectric material and electrodes, the minimum applied electric field that results in breakdown.

SI unit for gravitational field strength?

Newton's definition of gravitational force, F=Gm1m2/r2. G = 6.6742(10) x 10-11 m3 kg-1 s-2 or N m2 kg-2. The SI unit for gravitational field strength is G.

Is magnetism measured in watts?

Magnetism is not measured in watts, it is measured in teslas. The tesla (symbol T) is the SI derived unit of magnetic field strength or magnetic flux density, commonly denoted as B. One tesla is equal to one weber per square meter, and it was defined in 1960 in honour of Nikola Tesla. The strongest fields encountered from permanent magnets are from Halbach spheres, which can be over 4.5 T. The magnitude of the Earth's… Read More

Do SI Units remain the same no matter where the measurement is taken on the Moon or on Earth?

Yes, the idea is that the units don't depend on local conditions such as the gravitational field.

1-200 in si units?

SI units are defined for physical measurements, like measurements of mass, length, etc. - there are no specific SI units for plain numbers. SI units are defined for physical measurements, like measurements of mass, length, etc. - there are no specific SI units for plain numbers. SI units are defined for physical measurements, like measurements of mass, length, etc. - there are no specific SI units for plain numbers. SI units are defined for physical… Read More

The differnce between SI base units and SI derived units?

The base units are defined as such, the derived units can be obtained from the base units.

Why do scientists use SI units instead of units such as inches and gallons?

most of the world does SI so more people can understand with it in SI units

How many SI units?

The SI has 7 base units. These units can be combined in an almost unlimited way to form other (derived) units. The Wikipedia article on 'SI derived units' lists some examples.

What is the SI units of mass volume and density?

The SI units of mass is kilogram (kg). The SI units of volume is meters cube (m3). The SI units of density is kilograms per meters cube (kg/m3) (kg m-3)

The different between si units and metric units?

Si and metric are the same thing. SI was a redefinition of metric in 1960.

State SI and English units of mass?

SI units: kilogram, gram English units: pound-mass, slug

Why are SI units used so often in science?

SI units are more accurate than English system units

What does a Tesla measure?

The SI unit tesla (T) for measuring magnetic flux density or magnetic induction (commonly known as the magnetic field ) was named in Tesla¹s honour at the Conférence Générale des Poids et Mesures, Paris in 1960.

Would a meter be a basic unit of measurement?

Yes. It is one of the 7 basic units of the SI. Yes. It is one of the 7 basic units of the SI. Yes. It is one of the 7 basic units of the SI. Yes. It is one of the 7 basic units of the SI.

What are 7 SI units for chemistry?

There are seven quantities which have base units associated with themThese Quantities can be seen as : 1 . Length - meter . 2. Mass - kg. 3. Temperature - Kelvin . luminous Intensity - Candela. 5. Electric Current - Ampere . 6. Electric Current -ampere . 7.amount of substance = Mole

What is flux density?

Something that which produces a magnetic field The magnetic field that surrounds a magnet is made up of magnetic flux (symbol, the Greek letter 'phi'), usually represented as lines in field diagrams. The SI unit for measuring magnetic flux is the weber (pronounced 'vay-ber'). The intensity of this flux (the closeness of the lines in diagrams) is called the flux density (symbol: B). Flux density is greatest in the areas nearest a magnet's poles. Flux… Read More

What are SI Units and what does the SI stand for?

si units are based on the metric system system international (French) international system (English)

How can different units problems be overcome by using Si units?

The SI units are a universal standard, they are the same everywhere. If everyone uses the same units, there is no confusion.

What is the importance of SI Units?

the SI units are is the newton. it stands for Systeme International, unit of force.

An explosively pumped flux compression generator (EPFCG) is a device used to generate a high-power electromagnetic pulse by compressing magnetic flux using high explosive.

An EPFCG only ever generates a single pulse as the device is physically destroyed during operation. An EPFCG package that could be easily carried by a person can produce pulses in the millions of amperes and tens of terawatts.^{[citation needed]} They require a starting current pulse to operate, usually supplied by capacitors.

Explosively pumped flux compression generators are used to create ultrahigh magnetic fields in physics and materials science research^[1] and extremely intense pulses of electric current for pulsed power applications. They are being investigated as power sources for electronic warfare devices known as transient electromagnetic devices that generate an electromagnetic pulse without the costs, side effects, or enormous range of a nuclear electromagnetic pulse device.

The first work on these generators was conducted by the VNIIEF center for nuclear research in Sarov in Soviet Union at the beginning of the 1950s followed by Los Alamos National Laboratory in the United States.

• 2How it works
• 3The various types of generators

History[edit]

At the start of the 1950s, the need for very short and powerful electrical pulses became evident to Soviet scientists conducting nuclear fusion research. The Marx generator, which stores energy in capacitors, was the only device capable at the time of producing such high power pulses. The prohibitive cost of the capacitors required to obtain the desired power motivated the search for a more economical device. The first magneto-explosive generators, which followed from the ideas of Andrei Sakharov, were designed to fill this role.^[2][3]

How it works[edit]

Magneto-explosive generators use a technique called 'magnetic flux compression', described in detail below. The technique is made possible when the time scales over which the device operates are sufficiently brief that resistive current loss is negligible, and the magnetic flux through any surface surrounded by a conductor (copper wire, for example) remains constant, even though the size and shape of the surface may change.

This flux conservation can be demonstrated from Maxwell's equations. The most intuitive explanation of this conservation of enclosed flux follows from Lenz's law, which says that any change in the flux through an electric circuit will cause a current in the circuit which will oppose the change. For this reason, reducing the area of the surface enclosed by a closed loop conductor with a magnetic field passing through it, which would reduce the magnetic flux, results in the induction of current in the electrical conductor, which tends to keep the enclosed flux at its original value. In magneto-explosive generators, the reduction in area is accomplished by detonating explosives packed around a conductive tube or disk, so the resulting implosion compresses the tube or disk.^[4] Since flux is equal to the magnitude of the magnetic field multiplied by the area of the surface, as the surface area shrinks the magnetic field strength inside the conductor increases. The compression process partially transforms the chemical energy of the explosives into the energy of an intense magnetic field surrounded by a correspondingly large electric current.

The purpose of the flux generator can be either the generation of an extremely strong magnetic field pulse, or an extremely strong electric current pulse; in the latter case the closed conductor is attached to an external electric circuit. This technique has been used to create the most intense manmade magnetic fields on Earth; fields up to about 1000 teslas (about 1000 times the strength of a typical permanent magnet) can be created for a few microseconds.

Elementary description of flux compression[edit]

An external magnetic field (blue lines) threads a closed ring made of a perfect conductor (with zero resistance). The total magnetic flux ${\displaystyle \mathrm{\Phi }}$ through the ring is equal to the magnetic field ${\displaystyle B}$ multiplied by the area ${\displaystyle A}$ of the surface spanning the ring. The nine field lines represent the magnetic flux threading the ring.

Suppose the ring is deformed, reducing its cross-sectional area. The magnetic flux threading the ring, represented by five field lines, is reduced by the same ratio as the area of the ring. The variation of the magnetic flux induces a current (red arrows) in the ring by Faraday's law of induction, which in turn creates a new magnetic field circling the wire (green arrows) by Ampere's circuital law. The new magnetic field opposes the field outside the ring but adds to the field inside, so that the total flux in the interior of the ring is maintained: four green field lines added to the five blue lines give the original nine field lines.

Given The Magnetic Field 202 A/m: Test

By adding together the external magnetic field and the induced field, it can be shown that the net result is that the magnetic field lines originally threading the hole stay inside the hole, thus flux is conserved, and a current has been created in the conductive ring. The magnetic field lines are 'pinched' closer together, so the (average) magnetic field intensity inside the ring increases by the ratio of the original area to the final area.

The various types of generators[edit]

The simple basic principle of flux compression can be applied in a variety of different ways. Soviet scientists at the VNIIEF in Sarov, pioneers in this domain, conceived of three different types of generators:^[5][3][6]

• In the first type of generator (MK-1, 1951) developed by Robert Lyudaev, the magnetic flux produced by a wound conductor is confined to the interior of a hollow metallic tube surrounded by explosives, and submitted to a violent compression when the explosives are fired; a device of the same type was developed in the USA a dozen years later by C.M. (Max) Fowler's team at Los Alamos;
• The next type of generator (MK-2, 1952), the magnetic flux, confined between the windings of the external conductor and a central conductive tube filled with explosive, is compressed by the conical 'piston' created by the deformation of the central tube as the detonation wave travels across the device.
• A third type of generator (DEMG), developed by Vladimir Chernyshev, is cylindrical, and contains a stack of concave metallic disks, facing each other in pairs, to create hollow modules (with the number varying according to the desired power), and separated by explosives; each module functions as an independent generator.

Such generators can, if necessary, be utilised independently, or even assembled in a chain of successive stages: the energy produced by each generator is transferred to the next, which amplifies the pulse, and so on. For example, it is foreseen that the DEMG generator will be supplied by a MK-2 type generator.

Hollow tube generators[edit]

In the spring of 1952, R.Z. Lyudaev, E.A. Feoktistova, G.A. Tsyrkov, and A.A. Chvilevaundertook the first experiment with this type of generator, with the goal of obtaining a very high magnetic field.

The MK-1 generator functions as follows:

• A longitudinal magnetic field is produced inside a hollow metallic conductor, by discharging a bank of capacitors into the solenoid that surrounds the cylinder. To ensure a rapid penetration of the field in the cylinder, there is a slit in the cylinder, which closes rapidly as the cylinder deforms;
• The explosive charge placed around the tube is detonated in a manner that ensures that the compression of the cylinder commences when the current through the solenoid is at its maximum;
• The convergent cylindrical shock wave unleashed by the explosion produces a rapid contraction (greater than 1 km/s) of the central cylinder, compressing the magnetic field, and creating an inductive current, as per the explanation above (the speed of contraction permits, to first approximation, the neglect of Joule losses and the consideration of the cylinder as a perfect conductor).

The first experiments were able to attain magnetic fields of millions of gauss (hundreds of teslas), given an initial field of 30 kG (3 T) which is in the free space 'air' the same as H = B/μ₀ = (3 V_s/m²) / (4π × 10⁻⁷ V_s/Am) = 2.387×10⁶ A/m (approximately 2.4 MA/m).

Helical generators[edit]

Helical generators were principally conceived to deliver an intense current to a load situated at a safe distance. They are frequently used as the first stage of a multi-stage generator, with the exit current used to generate a very intense magnetic field in a second generator.

The MK-2 generators function as follows:

• A longitudinal magnetic field is produced in between a metallic conductor and a surrounding solenoid, by discharging a battery of capacitors into the solenoid;
• After the charge is ignited, a detonation wave propagates in the explosive charge placed in the interior of the central metallic tube (from left to right on the figure);
• Under the effect of the pressure of the detonation wave, the tube deforms and becomes a cone which contacts the helically wrapped coil, diminishing the number of turns not short-circuited, compressing the magnetic field and creating an inductive current;
• At the point of maximal flux compression, the load switch is opened, which then delivers the maximal current to the load.

The MK-2 generator is particularly interesting for the production of intense currents, up to 10⁸A (100 MA), as well as a very high energy magnetic field, as up to 20% of the explosive energy can be converted to magnetic energy, and the field strength can attain 2 × 10⁶ gauss (200 T).

The practical realization of high performance MK-2 systems required the pursuit of fundamental studies by a large team of researchers; this was effectively achieved by 1956, following the production of the first MK-2 generator in 1952, and the achievement of currents over 100 megaamperes from 1953.

Disc generators[edit]

A DEMG generator functions as follows:

• Conductive metallic discs, assembled in facing pairs to create hollow modules having the form of a lined torus, with explosive packed between pairs of modules, are stacked inside a cylinder;^[7] the number of modules can vary according to the desired power (the figure shows a device of 15 modules), as well as the radius of the discs (of the order of 20 to 40 cm).
• Current runs through the device, supplied by a MK-2 generator, and an intense magnetic field is created inside each module.
• When initiated, the explosion begins on the axis and propagates radially outwards, deforming the disc shaped protuberances with triangular section and pushing them away from the axis. The outward movement of this section of conductor plays the role of a piston.
• As the explosion proceeds, the magnetic field is compressed in the inside of each module by the conductive piston and the simultaneous drawing together of the inner faces, also creating an inductive current.
• As the induced current attains its maximum, the fuse opening switch fuses and the load switch simultaneously closes, allowing the current to be delivered to the load (the mechanism for the operation of the load switch is not explained in available documentation).

Systems using up to 25 modules have been developed at VNIIEF. Output of 100 MJ at 256 MA have been produced by a generator a metre in diameter composed of three modules.

See also[edit]

References[edit]

1. ^Solem, J. C.; Sheppard, M. G. (1997). 'Experimental quantum chemistry at ultrahigh magnetic fields: Some opportunities'. International Journal of Quantum Chemistry. 64 (5): 619–628. doi:10.1002/(sici)1097-461x(1997)64:5<619::aid-qua13>3.0.co;2-y.
2. ^Terletskii, Ia. P. (August 1957). 'Production of Very Strong Magnetic Fields by Rapid Compression of Conducting Shells'(PDF). JETP. 5 (2): 301–202.
3. ^ ^abSakharov, A. D. (7 December 1982). Collected Scientific Works. Marcel Dekker. ISBN978-0824717148.
4. ^Other techniques exist which do not depend on explosives. Notably, see: Flux compression scheme used at the Gramat centre of study, doctoral thesis, Mathias Bavay, 8 July 2002
5. ^Sakharov, A. D. (January 1966). 'Взрывомагнитные генераторы'(PDF). Uspekhi Fizicheskikh Nauk (in Russian). 88 (4): 725–734. Translated as: Sakharov, A. D. (1966). 'Magnetoimplosive generators'. Soviet Physics Uspekhi. 9 (2): 294–299. Bibcode:1966SvPhU...9..294S. doi:10.1070/PU1966v009n02ABEH002876. Republished as: Sakharov, A. D.; et al. (1991). 'Взрывомагнитные генераторы'(PDF). Uspekhi Fizicheskikh Nauk (in Russian). 161 (5): 51–60. doi:10.3367/UFNr.0161.199105g.0051. Translated as: Sakharov, A. D.; et al. (1991). 'Magnetoimplosive generators'. Soviet Physics Uspekhi. 34 (5): 387–391. Bibcode:1991SvPhU..34..385S. doi:10.1070/PU1991v034n05ABEH002495.
6. ^Younger, Stephen; Lindemuth, Irvin; Reinovsky, Robert; Fowler, C. Maxwell; Goforth, James; Ekdahl, Carl (1996). 'Lab-to-Lab Scientific Collaborations Between Los Alamos and Arzamas-16 Using Explosive-Driven Flux Compression Generators'(PDF). Los Alamos Science (23).
7. ^In practice, each prefabricated element, destined to be assembled into a cylinder, corresponds to an explosive device surrounded by two discs, which explains why the line of disks is terminated at each end by a hollow half module.

External links[edit]