Electric Field Changes Cause Magnetic Field
3:45 PM |
The change
of electric field gives rise to magnetic field is basically known by
physicist in 19th century. But change of electric field cause new
magnetic field is described by certain by James Clerk Maxwell. Maxwell
points out that electric and magnetic phenomena can be described using
equations involving electric fields and magnetic fields. The equation is called the Maxwell equation is the basic equation for the electromagnet.
Based on the rule, Maxwell put forward a hypothesis as follows: "Since the magnetic field changes can generate an electric field, the change of electric field will also cause a change of magnetic field". The hypothesis is used to explain the occurrence of electromagnetic waves.
If we look at the two antenna rods that function as an "antenna" it looks like in figure (a) above. If the two ends of the antenna are connected to the poles of a voltage source (eg battery) through a switch, when the switch is closed, the upper and upper-charged rods are negatively charged, so that an electric field will form, as shown by the lines in the drawing B) above. When the charge flows, a current appears in the direction of the arrow. Therefore, around the antenna will appear a magnetic field. The magnetic field lines (B) surround the wire so that in the image area, B enters (⊗) on the right and exit (Θ) on the left. The magnetic field and the electric field together store energy, and this energy can not be moved to distant places with infinite speed.
Next, we notice when the antenna is connected to the AC generator, it looks like the picture above. In the picture (a) above the connection is just connected and the sign (+) and (-) indicates the type of charge on each bar. The arrows indicate the direction of the current. The electric field is represented by the lines in the plane of the drawing, whereas the magnetic field corresponds to the right-hand rule of pointing inward (⊗) or outward (Θ) the plane of the image. In figure (b) above, the direction of the AC generator emf has changed so that the current is reversed and the new magnetic field has the opposite direction. Thus, a change of magnetic field produces an electric field and a change of electric field generates a magnetic field.
The values of E and B in the radiation field are known to decrease with distance of 1 / r ratio. The energy carried by the electromagnetic waves (waves in general) is proportional to the square of amplitude (E2 or B2), so that the intensity of the waves is reduced by 1/r2.
When the source emf converts sinusoidally, the electric field strength and magnetic field in the radiation field will also change sinusoidally. The sinusoidal nature of electromagnetic waves is shown in the figure above, which shows the field strength described as a function of position. The direction of vibration B and E is perpendicular to each other, and perpendicular to the direction of its propagation. These waves are called electromagnetic waves (EM). Electromagnetic waves include transverse wave types. Electromagnetic waves are generated by an oscillating electric charge, which accelerates. In general it can be said that the accelerated electrical charge generates electromagnetic waves. The speed or speed of electromagnetic wave propagation in air or vacuum is formulated:
The above equation, derived by Maxwell, then by entering the value of ε0 = 8,85 x 10-12 C2/M.m2, and μ0 = 4π × 10-7 N.s2/C2 are obtained :
The value of v ≈ 3.00 × 108 m / s is equal to the measured light rate. Where ε0 is the permittivity constant of vacuum and μ0 is the permeability constant of the vacuum. The above maxwell hypothesis and experiment proves that the electric field change causes magnetic field.
Maxwell's Hypothesis on the Changing of Electric Fields Invokes Magnetic Fields
The hypothesis proposed by Maxwell refers to the following three basic electric-magnetic rules.- The electric charge can produce an electric field around it (Coulomb's Law).
- An electric current or a flowing electric charge can produce a magnetic field around it (Biot-Savart Law).
- Changes in the magnetic field can produce an electric field (Faraday's Law).
Based on the rule, Maxwell put forward a hypothesis as follows: "Since the magnetic field changes can generate an electric field, the change of electric field will also cause a change of magnetic field". The hypothesis is used to explain the occurrence of electromagnetic waves.
Maxwell's Experiment About Electric Field Changes Sparks Magnetic Fields
Maxwell experimented on two insulators, each tied to the end of a spring and given a different charge (positive and negative). Then, the spring is vibrated so that the distance between the two charges changes, causing the two charges to create an alternating electric field. Changes in the electric field will cause a changing magnetic field as well. And from the magnetic field changes that occur, will cause the electric field back. And so on so that there is an uninterrupted process. Electrical field propagation E and magnetic field B are perpendicular to each other simultaneously called electromagnetic waves.If we look at the two antenna rods that function as an "antenna" it looks like in figure (a) above. If the two ends of the antenna are connected to the poles of a voltage source (eg battery) through a switch, when the switch is closed, the upper and upper-charged rods are negatively charged, so that an electric field will form, as shown by the lines in the drawing B) above. When the charge flows, a current appears in the direction of the arrow. Therefore, around the antenna will appear a magnetic field. The magnetic field lines (B) surround the wire so that in the image area, B enters (⊗) on the right and exit (Θ) on the left. The magnetic field and the electric field together store energy, and this energy can not be moved to distant places with infinite speed.
Next, we notice when the antenna is connected to the AC generator, it looks like the picture above. In the picture (a) above the connection is just connected and the sign (+) and (-) indicates the type of charge on each bar. The arrows indicate the direction of the current. The electric field is represented by the lines in the plane of the drawing, whereas the magnetic field corresponds to the right-hand rule of pointing inward (⊗) or outward (Θ) the plane of the image. In figure (b) above, the direction of the AC generator emf has changed so that the current is reversed and the new magnetic field has the opposite direction. Thus, a change of magnetic field produces an electric field and a change of electric field generates a magnetic field.
The values of E and B in the radiation field are known to decrease with distance of 1 / r ratio. The energy carried by the electromagnetic waves (waves in general) is proportional to the square of amplitude (E2 or B2), so that the intensity of the waves is reduced by 1/r2.
When the source emf converts sinusoidally, the electric field strength and magnetic field in the radiation field will also change sinusoidally. The sinusoidal nature of electromagnetic waves is shown in the figure above, which shows the field strength described as a function of position. The direction of vibration B and E is perpendicular to each other, and perpendicular to the direction of its propagation. These waves are called electromagnetic waves (EM). Electromagnetic waves include transverse wave types. Electromagnetic waves are generated by an oscillating electric charge, which accelerates. In general it can be said that the accelerated electrical charge generates electromagnetic waves. The speed or speed of electromagnetic wave propagation in air or vacuum is formulated:
The above equation, derived by Maxwell, then by entering the value of ε0 = 8,85 x 10-12 C2/M.m2, and μ0 = 4π × 10-7 N.s2/C2 are obtained :
v = 
v = 2,99792458 × 108 m/s ≈ 3,00 × 108 m/sThe value of v ≈ 3.00 × 108 m / s is equal to the measured light rate. Where ε0 is the permittivity constant of vacuum and μ0 is the permeability constant of the vacuum. The above maxwell hypothesis and experiment proves that the electric field change causes magnetic field.
0 Comment:
Post a Comment