# Electric field strength at a point between charges

In summary, the electric field strength at point B between two charges with magnitudes of 4.0×10-6 C and -1.0×10-6 C, separated by distances of 0.4 m and 0.3 m respectively, is 325000 N/C. However, the direction of the electric field must also be specified for a complete answer.
Find the electric field strength at point B between two charges shown below:

Given/Known Values
q1 = 4.0×10-6 C
r1 = 40 cm = 0.4 m (Distance from q1 to point B)
q2 = -1.0×10-6 C
r2 = 30 cm = 0.3 m (Distance from q2 to point B)
k = 9.0×109 Nm2/C2

Equations
Electric Force:
FE = (k⋅q1⋅q2)/r2
FE = q⋅E​

Electric Field:
E = (k⋅q)/r2
My thought process was that I could find the electric field strengths of both charges, and then find the difference between them, since point B is between the two charges.

E1 = (k⋅q1)/r12
= (9.0×109⋅4.0×10-6)/0.42
= 225000 N/C

E2 = (k⋅q2)/r22
= (9.0×109⋅-1.0×10-6)/0.32
= -100000 N/C

ΔE = EB = E1 - E2
= 225000 - (-100000)
= 325000 N/C

I'm not really sure if this is the correct way of finding the electric field strength of point B. Any help would be appreciated!

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Find the electric field strength at point B between two charges shown below:

Given/Known Values
q1 = 4.0×10-6 C
r1 = 40 cm = 0.4 m (Distance from q1 to point B)
q2 = -1.0×10-6 C
r2 = 30 cm = 0.3 m (Distance from q2 to point B)
k = 9.0×109 Nm2/C2

Equations
Electric Force:
FE = (k⋅q1⋅q2)/r2
FE = q⋅E​
Electric Field:
E = (k⋅q)/r2
My thought process was that I could find the electric field strengths of both charges, and then find the difference between them, since point B is between the two charges.

E1 = (k⋅q1)/r12
= (9.0×109⋅4.0×10-6)/0.42
= 225000 N/C

E2 = (k⋅q2)/r22
= (9.0×109⋅-1.0×10-6)/0.32
= -100000 N/C

ΔE = EB = E1 - E2
= 225000 - (-100000)
= 325000 N/C

I'm not really sure if this is the correct way of finding the electric field strength of point B. Any help would be appreciated!
I get the same numerical answer. To complete the problem, you need to specify the direction of the ##\vec E## vector.

#### Attachments

• 219yzj4.jpg
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## 1. What is electric field strength at a point between two charges?

Electric field strength at a point between two charges is a measure of the force that a charge would experience if placed at that point. It is dependent on the magnitude and distance of the charges.

## 2. How is electric field strength at a point between charges calculated?

Electric field strength at a point between charges can be calculated using the equation E = kQ/r^2, where k is the Coulomb's constant, Q is the magnitude of the charge, and r is the distance between the charges.

## 3. What is the unit for electric field strength?

The unit for electric field strength is Newtons per Coulomb (N/C).

## 4. How does the direction of electric field strength at a point between charges affect the motion of a charged particle?

The direction of electric field strength at a point between charges determines the direction of the force that the charged particle will experience. The particle will move in the direction of the force, either towards or away from the charges depending on the polarity of the charges.

## 5. Is electric field strength the same at all points between two charges?

No, the electric field strength at a point between two charges is not the same at all points. It varies depending on the distance from the charges and the direction of the point from the charges.

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