2. CONTENTS
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S.No
1. Magnetism
2. Magnets
3. Electromagnet
4. Electromagnetic Induction
5. Electric Current
6. Electric Power
3. MAGNETISM
+ Magnetism is a force that causes certain materials to attracts or repel
each other.
+ This force is caused by the motion of electrons within atoms.
+ When electrons spin in the same direction,they create a magnetic
field.
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4. + There are three types of magnets;
+ Naturally occurring magnets,
+ Artificially induced permanent magnets,
+ Electromagnets
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MAGNETS
5. + Many materials are unaffected when brought into a magnetic field. Such materials
are nonmagnetic and include substances such as wood and glass.
+ Diamagnetic: Weakly repelled
e.g. Water and Plastic.
+ Ferromagnetic: Strongly attracted by a magnet
e.g. Iron, cobalt, and nickel.
+ Paramagnetic: Lie somewhere between ferromagnetic and nonmagnetic
e.g. Contrast agents used in MRI are paramagnetic
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6. + An Electromagnet is a magnet that is created by the flow of electric current through
wire.
+ The strength of the magnetic field can be controlled by varying the amount of current
flowing through the wire.
+ Electromagnets are used in a wide range of applications, from electric motors
to MRI machines.
+ A moving charge creates a magnetic field called electromagnetism.
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ELECTROMAGNET
7. + Magnetic induction is the process of creating a magnetic field in a material by placing
it in a magnetic field.
+ When a magnetic material is placed in a magnetic field, the electrons in the material
align themselves with the magnetic field, creating a net magnetic field.
+ This process is used in the construction of transformers and electric generators.
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ELECTROMAGNETIC
INDUCTION
8. + Electric current is the flow of electric charge in a circuit.
+ Measured in Ampere (A)
+ Ohm’s law
+ Ohm’s law states that the current flowing through a conductor is directly proportional to voltage across
it, and inversely proportional to its resistance.
Where,
I =current
V= voltage
R= resistance
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ELECTRIC CURRENT
I = V/R
9. + Electric power is the rate at which electrical energy is transferred or consumed in a
circuit.
+ Measures in Watts (W)
+ Represented by “P”
Where,
V = voltage
I = current
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ELECTRIC POWER
P = VI