Firdiana Sanjaya Ana Alina

Magnetism Every magnet of whatever shape has two poles,designated the north and south poles The like poles of two magnets repel each other and the unlike poles attrack each other. With a typical bar magnet, for example, the field goes from the north pole to the south pole outside the magnet, and back from south to north inside the magnet. The relationship between magnetism and electricity shown that a changing magnetic field creates an electric field and a changing electric field creates a magnetic field.

The magnetic field produced by currents in wires  The magnitude of the field at a distance r from a wire carrying a current I is given by:  The field at the center of a circular loop of radius r carrying a current I is given by:  For N loops put together to form a flat coil, the field is just multiplied by N:  The field along the axis of the solenoid has a magnitude of:

Right-hand rule the vector v is in the direction of your thumb and B in the direction of your fingers. The force FB on a positive charge is in the direction of your palm, as if you are pushing the particle with your hand.

The force on a charged particle in a magnetic field Experiments on various charged particles moving in a magnetic field give the following results:  The magnitude F B of the magnetic force exerted on the particle is proportional to the charge q and to the speed v of the particle.  The magnitude and direction of F B depend on the velocity of the particle and on the magnitude and direction of the magnetic field B.  When a charged particle moves parallel to the magnetic field vector, the magnetic force acting on the particle is zero.

Magnetic Force Acting on a Current- Carrying Conductor B directed out of the page B directed into the page DIRECTION OF B

Magnetic Force Acting on a Current- Carrying Conductor

Torque on a Current Loop in a Uniform Magnetic Field For the magnetic field is parallel to the plane of the loop

Torque on a Current Loop in a Uniform Magnetic Field

Motion of a Charged Particle in a Uniform Magnetic Field  The particle moves in a circle because the magnetic force F B is perpendicular to v and B and has a constant magnitude qvB. As Figure illustrates, the rotation is counterclockwise for a positive charge. If q were negative, the rotation would be clockwise.

The Cyclotron  A cyclotron is a device that can accelerate charged particles to very high speeds. The energetic particles produced are used to bombard atomic nuclei and thereby produce nuclear reactions of interest to researchers. A cyclotron consists of an ion source at P, two dees D1 and D2 across which an alternating potential difference is applied, and a uniform magnetic field.(The south pole of the magnet is not shown.) The red dashed curved lines represent the path of the particles.

The Hall Effect  When a current-carrying conductor is placed in a magnetic field, a potential difference is generated in a direction perpendicular to both the current and the magnetic field.This phenomenon is known as the Hall effect.

The Hall Effect

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QUESTION  Andika How to get this formula :  Lakha What is the direction of magnetic field? Is that from north to south?  Hanif How can magnetic field create electric field?