Strength of an electrostatic field

It is convenient to describe a field by the force characteristic —strength of an electrostatic field E. At a point A, the vector magnitude E is ntrmerically equal to force, acting on the positive dimensionless (point) unit charge. 

The field created by an extended body can be obtained by integration over the whole volume of a body V  

The integral from vector quantity can be calculated, having expanded the vector onto components along the unit orts vectors 

There is no problem calculating the integral from the scalar function. 

The electric field is created by two point charges 2i and 22- The distance between the charges is d. Determine the strength of electrostatic field at a point which is removed at a distance from the first charge and f2 from the second. The numerical values are 2i = 30 nC, 22= 10 nC, = 15 cm and r2 = 10 cm. 

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The field is created by a uniformly charged thin rod of length I with a linear charge density r. Define the strength of an electrostatic field at a point A lying on the line of the charged rod at a distance d from its end. Numerical values are t = 1.2 yuC/m, / = 10 cm and d = 5 cm. 

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