Experiment 1 Amperes Rule Biology Essay

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Amperes Law is used to determine the magnitude and direction of the magnetic field which induced by an electric current. Ampere's Rule, somehow also called Right Hand Rule shows that induced magnetic field direction is perpendicular to the electric current. Ampere's law introduces a mathematical relationship to calculate the magnetic field from the total amount of electric current flowing enclosed by a closed loop. [3, 4]

The magnetic field forms concentric circles around a long wire which carries an electric current. Right hand rule is applied where thumb is pointed to the direction of electric current while fingers are curled to wrap around the wire. The direction of the magnetic field is perpendicular to the wire as shown in the figure below. [3, 4]

Figure -1: Right Hand Rule [Adapted from R. Nave, 1997]

Here, the objectives of this experiment are to understand the types and properties of magnets and to learn how to operate relays.

Material and Methodology:

The equipments that had been used in this experiment are Magnetism System Trainer (EMST-1600), Main Module (ULT-3000), and Module EM-06.

Firstly, the module EM-06 was set on the main unit ULT-3000, and the circuit a was located. The experiment circuit with 2mm stackable test leads was completed with the compass needle was perpendicular with the wire according to Figs. 1-2 and 1-3.

Figure 1-3: Circuit a When SW1 is Pressed

Then, +5V to V+ and -5V to V- were applied. The compass was approach to the single wire. After that, SW1 was pressed to observe the deflection of the compass needle. The time of SW1 ON should not be pressed too long, which approximately in few seconds only. The deflecting direction of the compass needle was observed. Next, the experiment circuit with stackable test leads was completed according to Figs. 1-4 and 1-5 then SW2 was pressed. The deflection of the compass needle was observed.

After that, circuit b on the module EM-06 was used and steps above were repeated. The position of compass needle was still the same as before. The results of circuit b were then compared with those of circuit a. In last step, the board was rotated 90&deg; so that the compass needle in circuit a was parallel with the wire and the procedures above were repeated.

a

2&deg; anticlockwise

15&deg; clockwise

15&deg; clockwise

60&deg; anticlockwise

b

1&deg; anticlockwise

10&deg; clockwise

5&deg; anticlockwise

30&deg; clockwise

Discussion:

From the result obtained, it is obviously shown that the compass needle deflected when either SW1 or SW2 were pressed. When switch was on, there is current flowing through the circuit. The deflection of the compass needle is due to the magnetic field that induced by the electric current. In the other word, current gives rise to magnetic fields, there is magnetic field around the wire. The deflection of the compass needle is very slightly.

For circuit a, the direction of the compass needle changes as discussed in the right hand rule. However in circuit b, relay races are considered here. If the magnet poles are the same polarity, they repel from each other. In contrast, if their poles are opposite, they attract each other. Hence in the circuit b case, there are two compasses. The two magnetic fields around the wire will repel each other then causes the different deflection direction of the compass needles.

Conclusion:

Right Hand Rule is learnt in this experiment to determine the direction of magnetic field. The types and properties of magnet are learnt and also the method of operating relay.

Introduction and Objectives:

Magnetic field induces a force on a moving electric charge or current. The direction of this force is given by the Fleming's left hand rule. Hence this rule determines the movement of a current carrying conductor in a magnetic field.

Figure 2-2: Illustration of Fleming's Left Hand Rule

Based on Fleming's left hand rule, extend the index finger, the middle finger and the thumb of the left hand in such a way that these three fingers are mutually perpendicular to each other. If index finger points to the direction of magnetic field (M), the middle finger shows the direction of current (C), then the direction of the thumb is the direction of where conductor moves. Devices that use current carrying conductors and magnetic fields include electric motors, generators, loudspeakers and microphones. Fleming's left hand rule is also known as the Motor Rule.1

Besides this, the direction of force also can be predicted from Fleming's right hand rule.

Figure 2-3: Fleming's right-hand rule

The figure above is used to show the force on a moving positive charge. It is obviously shown that magnetic force (F) is perpendicular to both the magnetic field (F) and the current (C).

Fleming's right-hand rule is also called generator's rule where it is always used to describe the operation of power generators.

The objectives of this experiment are to familiar with Fleming's left-hand rule and also Fleming's right-hand rule.

Material and Methodology:

The equipments that had been used in this experiment were Magnetism System Trainer (EMST-1600), Main Module (ULT-3000), and Module EM-07.

Firstly, module EM-07 was set on the main unit ULT-3000, and the circuit a was located. The experiment circuit was completed with stackable test lead by applying +20V to V+ according to Figure 2-4.

Figure 2-4: Circuit a of EM-07

After that, the magnet was set so that the North pole facing upwards. SW1 was pressed and the movement of the wire was observed. The time of SW1 ON should not be too long where approximately 1 or 2 seconds.

Then, the experiment circuit with stackable test lead was completed by applying -20V to V- according to Figure 6-1. SW2 was on and the movement of the wire was observed. The time of SW2 ON should not be too long, which approximately 1 or 2 seconds. Next, the polarity of the magnet was changed and then procedure above was repeated. Circuit b was located and the experiment circuit was completed as in Fig. 2-5. The positive power (≤ +10V) was slowly raised and the brightness of the lamp was observed.

North Pole Facing Up

The wire moves forward to the magnet

No response

South Pole Facing Up

The wire moves away to the magnet

No response

Observation:

The brightness of the lamp increased as the power increased.

Discussion:

The result of the experiment shows that Fleming's rule is applied when determining the direction of the magnetic field, force and current to the circuit. The brightness of the lamp increased as the power increased because there is current flowing through the circuit. Since the power increased, the current will be increased where Ohm's Law is applied here.

A magnetic field would be generated around the wire if the wire conducting an electric current. There would be more current flows through the wire if the stronger the magnetic field. Additionally, the more current would be generated if the faster the wire passes through the field.5

Conclusion:

In this experiment, method of using Fleming's left-hand rule and also Fleming's right-hand rule was learnt to determine the direction of magnetic field, current, and the movement.

Introduction and Objectives:

Electromagnetic induction occurs when a moving magnetic field causing electron current to flow through a wire. When the magnet is closing near the wire, magnetic field moves electrons along the wire inducing a current flow. The magnetic field produced by a current-carrying wire is always perpendicular to that wire.2 Self-induction is then defined as the induction of an opposing EMF in a single coil by the changing of magnetic field. An example device constructed based on this effect is inductor.[2]

Inductance (L) is the proportional constant between the self-induced EMF (Æ) and the time rate of change of the current where the EMF is introduced as [6]

The objective of this experiment is to understand the self-induction of a coil and also to verify the phenomenon of self-induction.

Material and Methodology:

The equipments that were used in the experiment were Magnetism System Trainer (EMST-1600), Main Module (ULT-3000), and Module EM-08. Firstly, the module EM-08 was set on the main unit ULT-3000 and circuit a was located. According to Figure 3-1, the experiment circuit was completed with stackable test lead. Then +5V to V+ was applied. Lastly, the states of the lamp was observed while pressing or releasing SW1.

States of Lamp

The lamp is on where causes brightness.

The lamp is off. No response.

Discussion:

When the SW1 is pressed, there is current flowing through the circuit. From the circuit of Figure 3, the wire conducts the electric current then generates a magnetic field around the wire. In same condition, the magnetic field would pass through the wire then induces an electric current on the wire. Hence the reason of the lamp is lighted when SW1 on is due to there is electric current around the wire while when SW1 off causes no response to the light is because of no current at the circuit. In other words, the magnetic field will only move with the wire to generate current in the wire.

Conclusion:

After this experiment, the principle of self-induction of a coil was learnt and the phenomenon of self-induction was verified.

Introduction and Objectives:

When two coils of wire are arranged so that the change in current in one coil of wire causes induced voltage in the other coil, this effect is called mutual inductance. [6]

Transformer is a device invented according to the effect of mutual inductance between two or more coils. [2] There are two types of transformers, which are step-up transformer and step-down transformer. Step-up transformer is used to increase the voltage while step-down transformer is to decrease the voltage. A transformer consists of two insulated coils wound around a magnetic flux. A changing current in the primary inductor causes changes in magnetic field. This magnetic field then induces a changing voltage in the secondary inductor.

The step-up or step-down of voltages of transformer depend on the number of turns of wire, as shown in equation below: [3]

where Vp = primary voltage,

Vs = secondary voltage,

Np = number of primary turns,

Ns = number of secondary turns.

There are some factors of Induction Strength, which are the strength of the magnetic field, the velocity of the magnetic field as it moves past the conductor, the angle of the conductor to the magnetic field, the number of turns in the conductor. [6]

The objectives of this experiment are to understand the mutual-induction between coils, and verify the phenomenon of mutual-induction.

Material and Methodology:

The equipments that have been used in this experiment were Magnetism System Trainer (EMST-1600), Main Module (ULT-3000), and Module EM-08.

Firstly, the module EM-08 was set on the main unit ULT-3000, and circuit b was located.

Then, the experiment circuit was completed as shown in Figure 4-1 with stackable test lead.

Figure -1: Circuit b of EM-08

After +3V to V+ was applied, SW2 was pressed and the indication on the μA meter was observed. SW2 was released and the indication on the μA meter was observed. Next, SW2 was pressed and released continuously and the readings of μA meter were observed. The power supply was increase gradually up until 12V and step above was repeated. The results below were recorded.

0.275

0.361

0.383

0.369

0.408

0.430

0.431

0.460

0.473

12V

0.438

0.464

0.478

Observation:

There is current indication present on the µA meter when SW2 is pressed and no current indication after SW2 is released.

Discussion:

The result shows that while the voltage increases, the current also increases. There is current indication in the ammeter shows that there is magnetic flux through the circuit. The magnetic flux then induces the electric current. The change in current of coil of wire in inductor primary causes induced voltage in the other coil of inductor secondary.

Conclusion:

In conclusion, the relationships between mutual-induction between coils are learnt, and the phenomenon of mutual-induction was verified in this experiment.

Introduction and Objectives:

The magnetic field will exert a transverse force on the moving charge carriers when a current flows through a conductor. The transverse force tends to push the moving carriers to one side of the conductor. The sides of the conductors will produce charge and balance the magnetic influence which produces a measurable voltage between both sides of the conductor. This measureable transverse voltage is an effect called Hall Effect.

From the diagram below, it shows that the direction of the current I is a conventional electric current, hence the electrons move in the opposite direction. Hall Effect sensors consist of a multilayer structure including a thin layer of a semiconductor material deposited on a semiconductor substrate. The two layers are electrically isolated from each other. Magnetic field can be measured using Hall Effect with a Hall probe. Hall Effect is always used in the measurement of large magnetic fields as in Tesla. [7]

Figure -1: Hall Effect Diagram

The Hall voltage is given as the formula below: [4]

Where n = density of mobile charges

e = electron charge

The objective of this experiment is to learn the operating principle of a Radiometric Linear Hall Effect Sensor (Magnetic-flux-density sensor) and to understand the application of the magnetic flux detector circuit.

Material and Methodology:

The equipments of this experiment are Magnetism System Trainer (EMST-1600), Main Module (ULT-3000), and Module EM-08.

Firstly, the module EM-08 was set on the main unit ULT-3000, and the circuit c was located. +12V and -12V was applied to the experiment circuit as shown in Figure 5-2. The magnet was approached to HES1 and the output voltage on the voltmeter was observed.

1.93

1.88

2.10

2.10

2.10

1.93

LED1 on

LED1 on

LED1 and LED2 on

LED1 and LED2 on

LED1 and LED2 on

LED1 on

Discussion:

From the result obtained, the maximum voltage of both north or south poles of magnet is 2.10 V. And when the maximum voltage is reached, both LED1 and LED2 will on. While if voltage less than 2.10V, only one of the LEDs will on. When the magnet is approached to the sensor, there is a Lorentz force disturbing the current distribution, and then this will cause a voltage across the output. Hence, it can be shown that when the North Pole magnet approach sensor in rear direction, there is more current flows through the circuit and cause the higher voltage to light both LED1 and LED2. This condition is the applied also as in South Pole of magnet approaches sensor in front and top direction.

Conclusion:

In this experiment, the operating principle of a Radiometric Linear Hall Effect Sensor (Magnetic-flux-density sensor) as well as the application of the magnetic flux detector circuit is learnt.