Calculating electric field strength

In summary, the conversation involves calculating the electric field strength at three points (represented by O) using the equation F = kq/r^2. After making a mistake in the calculation, the individual realizes that the magnitude of the electric field strength is 1.39782 * 10^8 N/C, rather than the initially calculated 1.25072 * 10^8 N/C.
  • #1
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Homework Statement



http://img219.imageshack.us/img219/3310/problemi.png [Broken]

Homework Equations



F = kq/r^2

The Attempt at a Solution



O ----- x ----O -----------O

Let the electric field of the first O be E1, second be E2, third be E3.
RED - .02m
BLUE - .016m
GREEN - .033m

E1 = (9 * 10^9) (7.6 * 10^-6) / (.02^2) = 1.70763 * 10^8
E2 = (9 * 10^9) (1.6 * 10^-6) / (.016^2) = 5.61722 * 10^7
E3 = (9 * 10^9) (2.8 * 10^-6) / (.033 + .016)^2 = 1.04811 * 10^7

E1 and E3 are going -> and E2 is going <-.
So I figured the magnitude of the electric field strength would be the absolute value of E1 + E3 - E2 which turned out to be 1.25072 * 10^8 N/C.

However the answer is apparently wrong and I'm not sure where I made a mistake =\.
Any help is appreciated.

Never mind I caught my mistake after re-reading what I typed out...turns out I used 7.6 for the first charge instead of 7.9 :(
 
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  • #2
E1 = (9 * 10^9) (7.9 * 10^-6) / (.02^2) = 1.86453 * 10^8So the magnitude of the electric field strength is 1.39782 * 10^8 N/C.
 

What is electric field strength?

Electric field strength is a measure of the force felt by a charged particle within an electric field.

How is electric field strength calculated?

Electric field strength is calculated by dividing the force exerted on a charged particle by the magnitude of the charge of the particle. It is represented by the equation E = F/q, where E is electric field strength, F is the force, and q is the charge.

What units are used to measure electric field strength?

The SI unit for electric field strength is volts per meter (V/m), but it can also be measured in newtons per coulomb (N/C) or electron volts per meter (eV/m).

How does distance affect electric field strength?

The electric field strength is inversely proportional to the square of the distance from the source of the field. This means that as the distance increases, the electric field strength decreases.

What is the difference between electric field strength and electric potential?

Electric field strength measures the force felt by a charged particle, while electric potential measures the potential energy per unit charge at a certain point in the electric field. Electric field strength is a vector quantity, while electric potential is a scalar quantity.

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