electric field. how is one charge able to exert an electrical force on another charge even though...
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What enables Earth to exert a gravitational force on the Moon even though they are not in contact with each other?TRANSCRIPT
Electric field
How is one charge able to exert an electrical force on another charge even though the two charges are not in contact with each other?
What enables Earth to exert a gravitational force on the Moon
even though they are not in contact with each other?
The Concept of a FieldA field is defined as a property of space in which a material object experiences a force.
.PAbove earth, we say there is a gravitational field at P.Because a mass m experiences a downward force at that point.
No force, no field; No field, no force!
m
F
Analogy
The electric field is the field around an electrical charge
just like
a gravitational field is the field around a mass.
Field Near a Positive Charge
E
Electric Field++++ + +++Q
.r
The field E at a point exists whether there is a charge at that point or not. The direction of the field is away from the +Q charge.
E
Electric Field++++ + +++Q
.r
++q --q
Force on +q is with field direction.
Force on -q is against field
direction.
F
F
Field Near a Negative Charge
The field E in the vicinity of a negative charge –Q is toward the charge—the direction that a +q test charge would move.
Force on +q is with field direction.
Force on -q is against field
direction.
E
Electric Field
.r
++qF
---- - ----Q
E
Electric Field
.r
--qF
---- - ----Q
The Magnitude of E-FieldThe magnitude of the electric field intensity at a point in space is defined as the force per unit charge (N/C) that would be experienced by any test charge placed at that point.
Electric Field Intensity E
N; Units C
FEq
The direction of E at a point is the same as the direction that a positive charge would move IF placed at that point.
E around a positive and a negative charge
Drawing the electric field
Electric field due to a point charge
Essential Knowledge 2.C.2: The magnitude of the electric field vector is proportional to the net electric charge of the object(s) creating that field. This includes positive point charges, negative point charges, spherically symmetric charge distributions, and uniformly charged parallel plates.
E = electric field in N/Ck = Coulomb constant = 9.0 x 109 Nm2/C2
Q = charge causing the field in Cr = distance of a point form the charge Q in m
Equations you have to remember