Defining Electric Field around a charge

[Phynite]

Electric field around a charge or system of charges is defined as the force experienced per unit charge. Won't the original field be disturbed by the test charge's own field ? How then the original field be measured accurately ?

 

[dirac1933]

Hmm...How do I way this? Force and field are related concepts but not entirely the same thing.

First of all you would be right to say that the field in some space would be altered if you introduce a test charge or any charge for that matter into the "picture" and if I throw in another charge into the space, the field will change as a result. However when you measure a field, what you are essentially doing is probing the force per unit charge that your test charge experiences due solely to the contribution of the other charges in the system. You must remember that the an object cannot exert a force on itself .

I'm terrible at explaining stuff but hope this helps!

 

[jtbell]

Electric field around a charge or system of charges is defined as the force experienced per unit [test] charge

...in the limit as the magnitude of the test charge approaches zero.

 

[Pushpam Singh]

Yes, the original field will be disturbed by the test charge's own field.
It is considered that the value of the test charge taken is very low i.e. the minimum value of the test charge is taken so that the disturbance in the original field is minimum and this minimum disturbance can be neglected.

 

[sardar]

The presence of a test charge does indeed affect the electric field created by a charge or system of charges. This is because the test charge itself creates its own electric field, which interacts with the original field. However, this disturbance can be accounted for and the original field can still be accurately measured.

In order to measure the original field accurately, we must first understand that the electric field is a vector quantity. This means that it has both magnitude and direction. The direction of the electric field at a point is determined by the direction of the force that a positive test charge would experience at that point. The magnitude of the electric field is determined by the strength of the force and the distance from the charge.

When a test charge is introduced to the original field, it will experience a force due to both the original field and its own field. By measuring the force experienced by the test charge and knowing its own field, we can calculate the force due to the original field alone. This allows us to determine the direction and magnitude of the original field accurately.

In addition, scientists often use multiple test charges at different locations to measure the electric field. By analyzing the forces experienced by each test charge, the overall pattern and strength of the electric field can be determined.

In summary, while the presence of a test charge does affect the original electric field, it can still be measured accurately by considering the forces experienced by the test charge and using multiple test charges to analyze the overall field.