# Magnetic field strength determination on a

As the fluid moved, the magnetic field would go with it. The theorem describing this effect is called the frozen-in-field theorem. Even in a fluid with a finite conductivity, new field is generated by stretching field lines as the fluid moves in ways that deform it. The electric current is the rate of flow of electric charge through a conducting medium with respect to time. When there is a potential difference appeared between two points in a conductive medium electric charge starts flowing from higher potential point to lower potential point to balance the charge distribution between the points.

The rate of flow of charge in respect of time is known as electric current. Current Formula If q Coulomb electric charge gets transferred between these two points in time t sec, then the current can be calculated as In differential form, the current can be represented as Unit of Current As the current is the ratio of transferred charge to the time taken for this charge transferring we can say one unit current is such a rate of charge transferring in which one Coulomb charge is transferred from one point to another in one second.

This is SI unit of electric current. Theory of Electricity Current in Metallic Conductor The main cause of current through a metallic substance is the flow of electrons that is the directional drift of free electrons.

In metal, even at room temperature, there are plenty of free electrons exist inside the metallic crystal structure. When electric potential between two points in the metal differs the free electrons which were randomly moving at equilibrium potential condition and also the free electrons supplied by the source if a source is connected between these two points now get drifted towards higher potential point due to electrostatic attraction.

## What are magnetic fields? (article) | Khan Academy

As each of the electrons has a negative charge of - 1. The rate of flow of this negative charge in respect of time is the current in the metal. Conventional Direction of Current Although the flow of electrons or negative charge is from lower potential point to higher potential point but the conventional direction of current is considered from higher potential to lower potential.

Although current is mainly caused by the flow of electrons that is the flow of negative charge but previously it was thought that the electrical current is due to the flow of positive change.

But now it is proved that the current in a metallic conductor is due to flow of electrons or negative charge but the direction of current is still considered as it was accepted previously that is opposite of flow of electrons.

The direction of the current which is considered from a higher potential point to a lower potential point is known as the conventional direction of current. Types of Current Direct Current When current flows in one direction either in constant or fluctuating manner the current is called direct current. Alternating Current When current flows in either direction alternatingly in a frequency is called alternating current.

The average value of an alternating current is zero. The alternating current is measured in RMS value. One main parameter of alternating current is frequency. Magnetic Effect of Current When current flows through a conductor there will be a magnetic field surrounding the conductor. The direction of the lines of force of the magnetic field can be determined by right-hand grip rule.

If we imagine that we have held the current carrying conductor with our right hand with extended thumb along the direction of the current then four fingers of our right hand indicate the direction of lines of force of the magnetic field.

When we make a coil with a conductor and current flows through the coil then due to magnetic effect of each conductor of the coil there will be an overall magnetic field surrounding the coil. Here we can also determine the direction of the field by right-hand grip rule.

If we hold the current carrying coil with our four fingers along the direction of current in the turns of the coil then the extended thumb indicates the direction of the magnetic field.

Current in Magnetic Field When we place a current carrying conductor or a current carrying coil in a magnetic field, a mechanical force acts on the current carrying conductor or coil.

This mechanical force depends on the current through the conductor or coil. Measurement of Current Depending on the principle of interaction between current and magnetic field one can measure the current.

## Magnetic field - Wikipedia

One of the basic instruments to measure the current is pmmc instrument or permanent magnet moving coil instrument. The pmmc instrument is only able to measure direct current. The alternating current can be measured by moving iron instrument where magnetic field created by current through the instrument coil causes movement of a soft iron piece either by attraction or repulsion force.

This instrument can also measure direct current.

• What is Electric Current?
• Magnetic field - Wikipedia
• Current Formula
• What is Electric Current and Theory of Electricity

Rectifier type instruments are also used to measure alternating current. Here bridge rectifier is used to rectify alternating current then it is measured with pmmc instrument.

Wherever may be the types of current measuring instrument in one word all current measuring instruments are called ammeter. An ammeter is always connected in series with the path of which the current to be measured.

When very high current is to be measured we use current transformers to step down current for measuring purpose. Heating Effect of Current When current flows through a conductor there is a heating effect in the conductor. The loss of power in the conductor is i2R watts. The loss of energy is i2Rt joules.PHYS-UA 72 Intro to Exp Physics II Magnetic Field of a Circular Coil where B pp is the peak to peak value of the magnetic eld and!is the angular frequency of the alternating current.

B pp = B pp(~r) depends on position but not on the r-bridal.coming Eq.(2) and Eq.(3), the voltage across the search coil becomes. Sep 03,  · Edit Article How to Determine the Strength of Magnets. Three Methods: Determining Factors that Affect Magnetic Field Strength Testing Magnetic Field Range with Paperclips Testing Magnetic Field Strength With a Gaussmeter Community Q&A Magnets are commonly found in motors, dynamos, refrigerators, credit and debit 65%(20).

Practical Measurements of T1 and T2. Relaxation times can be measured in different ways with various degrees of ac­cu­ra­cy.

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In vitro Determination. High-resolution magnetic resonance spectroscopists have measured T1 values since the middle of the last century.

Use the different methods of measuring the magnetic fields and find this field at different positions from the bar magnet. Record both the field strength and the distance. The magnetic field strength is a measurement of the magnetic field’s strength and direction at a particular point near the magnet. It is expressed in Gauss or Tesla (1 Tesla = 10, Gauss). It depends on the size, shape and grade of the magnet, where the measurement is performed, and the presence of any other magnets or ferromagnetic .

## 04-06 Practical Measurements of T1 and T2

There's a magnetic field and you need to measure its strength. But how? Here are some options. Magnetic Compass —————-Back when I was a kid, we had these things called compasses.

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