Electric Field Intensity :
"The electric Field Intensity at a point in a space is equal to force per unit charge exerted on extremely small positive Charge placed at that point"
It's direction is that of the force that acts on the positive test charge
Consider A point charge '+Q' located at point 'O' in space , the charge '+Q' sets up Electric field in the space surrounding it.If a small positive test Charge "+q0" placed at point 'P' experience a force "F" and electric Field Intensity at point'P' given by
E = F/q0 Newton/Coulomb
F= qE
Consider a point charge '+Q' placed at point 'O' then the magnitude of Electric field Intensity at point'P' from a distance (OP=d) is given by
Electric field Intensity Due to a group of Point Charges :
The resultant Electric field Intensity at a point due to group of Point charges can be given by Super Position Principlethus Electric field Intensity at a point 'P' due to "n" point charges (Q1,Q2,Q3,......Qn)
E=E1+E2+E3+......................+En
Electric Lines Of Force (Field Lines ) :
The Electric field due to a group of charges is represented by Electric lines of force .this is a very useful visual representation of Electric field.
Properties of Electric lines of Force :
"The electric Field Intensity at a point in a space is equal to force per unit charge exerted on extremely small positive Charge placed at that point"
It's direction is that of the force that acts on the positive test charge
E = F/q0 Newton/Coulomb
F= qE
- Electric field Intensity is a vector quantity i.e it has both magnitude and direction
- The SI unit of Electric field Intensity is N/C . It can also expressed in Volts per metre V/m
Electric field Intensity Due To A Point Charge :
Consider a point charge '+Q' placed at point 'O' then the magnitude of Electric field Intensity at point'P' from a distance (OP=d) is given by
Electric field Intensity Due to a group of Point Charges :
The resultant Electric field Intensity at a point due to group of Point charges can be given by Super Position Principlethus Electric field Intensity at a point 'P' due to "n" point charges (Q1,Q2,Q3,......Qn)
E=E1+E2+E3+......................+En
Electric Lines Of Force (Field Lines ) :
The Electric field due to a group of charges is represented by Electric lines of force .this is a very useful visual representation of Electric field.
An electric line force is the path along which a small positive test Charge would move if free to do so.The number of field lines emerging from +ve charge is proportional to magnitude of Charge.
Properties of Electric lines of Force :
- The electric lines of force are directed away from positive Charge and towards the negative charge
- The field lines start at +ve charge and ends at -ve charge
- Field Lines leave or enter the charged surface normally
- Flux lines cannot pass through a conductor. This means the electric Field inside a conductor is zero
- Flux lines cannot intersect each other
- Field Lines have tendency to contract in length
- Electric lines of force have tendency to expand laterally
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