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Fields

What is field?

Every thing has it's own field and in that field they influence the objects. Magnets have magnetic field, Charges at rest have electric field, mass has gravitational field. We can say field is the space around an object in which any other object of same nature experiences force. The object which applies force is called source object and one experiences force is called test charges. The test object is negligibly small so its influence on the source object is zero. The image below shows the  test object. The dashed line shows the field of the object.

Electric Fields, Magnetic field

What is electrostatic fields?

Electric field is defined as the force per unit charge. Electric field  is vector quantity

E= F/q

In case of electric field, source charge and test charge both are taken positive.

What are electric field lines?

Electric field lines represent the direction of force experienced by test charge.

 

Lets say we are bringing a positive test charge (its default test charge for convention)  near a positive source charge then the force is repulsive and the test charge will move away from the source charge. So the direction of electric field lines are outward form the source charge as shown in the image below.

If a test charge left near the source charge then it will the follow one of the field lines. It means electric field lines also represent the motion of the electric charge.

Positive charge field lines, Negative ch

What is gravitational fields?

Similar to electric field gravitational field is defined as the force per unit mass. Gravitional field  is vector quantity

g= F/q

As the electric fields and gravitational fields are similar we can easily relate both of them.

What are gravitational field lines?

 

Lets say we are bringing a test mass (mass has no sign unlike charges)  near a source mass. The force attractive it means the test mass will move towards the source charge. So the direction of gravitational field lines are inward ( towards source mass) as shown in the image below.

Gravitational field lines.jpg

IBDP Physics Related Topics

  • Measurement and uncertainties

  • Mechanics

  • Thermal physics

  • Oscillation and waves

  • Electricity and magnetism

  • Circular motion and Gravitation

  • Atomic nuclear and particle physics

  • Energy production

  • Wave Phenomena

  • Field's

  • Electromagnetic induction

  • Quantum and nuclear physics

  • Relativity

  • Engineering physics

  • Astrophysics

IBDP gravitational fields
IBDP Electrostatic fields
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