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17. ELetric field

What is an electic field?

- It is a region in space where a body experience a force by virtue its charge and independent of its speed

Case 1: ELECTRIC FIELDS STRENGTH

What is meant by E.F.S?

-It is a vector quantity the force per unit unit positive charge acting on a stationary unit test charge

Part A (P2) Plate

Formula : E = V /D

unit : Vm

graph 2

Part B (P4) shere

Formula : E

Gauss's theorem

unit :N/c

graph

Everest goes up for +ve charge

case 2 : E-force

state coulomb's law

the electrostatic force between two point charge is directly proportional to the product pf their magnitude and inevrsely proportiona to the square of the distance between their centre

NOTE

applied to point charge

seperation of the sphere is large compared to their radi

force can act throught empty space or vaccum

formula =

graph

unit =N

how does shows that it is an inverse square law field ?

within a uniform force field the magnitude of the force at a point is inversely propotional to the square of the distance from the point source which generatessuch field

Case 3 : E-potential

what is meant the Ep at a point?

It is the workdone per unit positive charge in bringing the charge from infinity to the point concerned,irrespective of the path taken

The EP at a point due to a system of point charge is given by the agebric sum of potentials due to the individual charhes . The SI unit is JC

NOTE :

potential is zero at infinty

relationship btw E.F.S and potential

E= -dV/ adx

+ve W.D = repulsice force

-ve w.D = attractive force

graph

OFFSHOOT

1) milkan 's oil drop expt

equilibrium ==> electric force = weight

2) electron gun

1/2 mv 2 =eV

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