解答五 27.51. (a) Identify: Use Eq. (27.2) to relate Set Up: The
... EVALUATE: v1 v2 . v2 is perpendicular to B whereas only the component of v1 perpendicular to B contributes to the force, so it is expected that F2 F1, as we found. 28.43.IDENTIFY: Apply Ampere’s law. SET UP: To calculate the magnetic field at a distance r from the center of the cable, apply Ampe ...
... EVALUATE: v1 v2 . v2 is perpendicular to B whereas only the component of v1 perpendicular to B contributes to the force, so it is expected that F2 F1, as we found. 28.43.IDENTIFY: Apply Ampere’s law. SET UP: To calculate the magnetic field at a distance r from the center of the cable, apply Ampe ...
G. Maxwell`s Equations: Integral Form
... We would like to verify here that nature always opposes us. The figure at the left indicates an initial B(t) varying as a quadratic function of time t. This increasing magnetic flux produces the circular E vector field in the counterclockwise direction using the B-Left right. The produced E field is ...
... We would like to verify here that nature always opposes us. The figure at the left indicates an initial B(t) varying as a quadratic function of time t. This increasing magnetic flux produces the circular E vector field in the counterclockwise direction using the B-Left right. The produced E field is ...
Document
... Magnetic Resonance Imaging • In effect, the magnetic field makes the protons act like tiny radio transmitters that only broadcast their signal when the value of the magnetic field is just right • By varying the strength of the magnetic field as a function of position in the body, the spin flips can ...
... Magnetic Resonance Imaging • In effect, the magnetic field makes the protons act like tiny radio transmitters that only broadcast their signal when the value of the magnetic field is just right • By varying the strength of the magnetic field as a function of position in the body, the spin flips can ...
Handout Topic 5 and 10 -11 NEW Selected Problems 3
... 10. This question is about the force between current-carrying wires. Diagram 1 below shows two long, parallel vertical wires each carrying equal currents in the same direction. The wires pass through a horizontal sheet of card. Diagram 2 shows a plan view of the wires looking down onto the card. ...
... 10. This question is about the force between current-carrying wires. Diagram 1 below shows two long, parallel vertical wires each carrying equal currents in the same direction. The wires pass through a horizontal sheet of card. Diagram 2 shows a plan view of the wires looking down onto the card. ...
W10D1
... Electric Currents and Magnetic Fields Electromagnet • Iron bar placed in a current-carrying coil • Most powerful—employs superconducting coils that eliminate the core • Applications – control charged-particle beams in high-energy accelerators – lift automobiles and other iron objects – levitate and ...
... Electric Currents and Magnetic Fields Electromagnet • Iron bar placed in a current-carrying coil • Most powerful—employs superconducting coils that eliminate the core • Applications – control charged-particle beams in high-energy accelerators – lift automobiles and other iron objects – levitate and ...
Magnetic Field Lines
... In the photosphere magnetograms show that there are regions of opposite polarity that are separated by a magnetic polarity inversion line. When the magnetic field joins the opposite polarities across this inversion line the field forms a “coronal arcade”. These arcades of magnetic field lines are cl ...
... In the photosphere magnetograms show that there are regions of opposite polarity that are separated by a magnetic polarity inversion line. When the magnetic field joins the opposite polarities across this inversion line the field forms a “coronal arcade”. These arcades of magnetic field lines are cl ...
How lasers work Simulated emission Population Inversion The laser
... MRI- how does it work? • MRI works by locating the hydrogen atoms inside the body. Since the body is mostly water, there are lots of hydrogen atoms • the nucleus of a hydrogen atom is a single protons. Protons behave like tiny bar magnets with a north pole at one end and a south pole at the other en ...
... MRI- how does it work? • MRI works by locating the hydrogen atoms inside the body. Since the body is mostly water, there are lots of hydrogen atoms • the nucleus of a hydrogen atom is a single protons. Protons behave like tiny bar magnets with a north pole at one end and a south pole at the other en ...
Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets usually consist of a large number of closely spaced turns of wire that create the magnetic field. The wire turns are often wound around a magnetic core made from a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a more powerful magnet.The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.Electromagnets are widely used as components of other electrical devices, such as motors, generators, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel.