Electric field strength due to two point charges

In summary, the conversation discusses two charges (+1 X 10^-6 and 3 X 10 ^ -6) that are 10 cm apart and a point that is 4 cm away from the +1 X 10^-6 charge. The discussion also mentions the need to plot the electric field strength as a function and the behavior of the field on the outside and in the middle of the two charges. The conversation ends with a rough sketch of the expected electric field strength values between the two charges.
  • #1
stunner5000pt
1,461
2
Given are two charges +1 X 10^-6 and one 3 X 10 ^ -6 distnace of 10 cm apart

I know there is a poitn in between these two and it is 4 cm from the 1.0 X 10^-6 charge

But i am asked to plot the elctric field strength as a function
if the elctric field is pointing right, then positive, otherwise if poitning left, then negative

Let what happens on the outside of these two charges be, i can figure that on my own

But what happen in the middle


Point at 4 cm and rises after??

(+)------------- (+)

Negative
 
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  • #2
stunner5000pt said:
Given are two charges +1 X 10^-6 and one 3 X 10 ^ -6 distnace of 10 cm apart

I know there is a poitn in between these two and it is 4 cm from the 1.0 X 10^-6 charge

3.66 cm, you mean? (It is not 4.00 cm for sure so I assume you rounded off)

But i am asked to plot the elctric field strength as a function
if the elctric field is pointing right, then positive, otherwise if poitning left, then negative

Let what happens on the outside of these two charges be, i can figure that on my own

But what happen in the middle


Point at 4 cm and rises after??

(+)------------- (+)

Negative


I hope you only have to roughly sketch the result because it's not a simple function to draw at all. But it starts at + infinity near the left charge, decreases sharply, crosses into the negative values as you pass the 3.66 cm mark (assuming the left charge is the 1 microcoulomb), goes down and approaches -infinity near the right charge.

Unfortunately, I have to leave (it's midnight here and I am still in my office. And I am teaching tomorrow at 8h30!).

Good luck with your questions!

Pat
 
  • #3
(-) | 4 cm | (+)

The electric field strength at the point 4 cm from the +1 X 10^-6 charge and 6 cm from the +3 X 10^-6 charge can be calculated using the formula:

E = k*q/r^2

Where:
E - electric field strength
k - Coulomb's constant (9x10^9 Nm^2/C^2)
q - charge of the point charge
r - distance between the point charge and the point at which the electric field is being measured

In this case, the electric field at the point 4 cm from the +1 X 10^-6 charge and 6 cm from the +3 X 10^-6 charge can be calculated as:

E = (9x10^9 Nm^2/C^2) * (1 X 10^-6 C) / (0.04 m)^2 = 562.5 N/C

Since the two charges are of opposite signs, the electric field at this point will be directed towards the +3 X 10^-6 charge, making it positive. This means that the electric field strength is pointing to the right.

On the other hand, if we consider a point between the two charges, for example at 5 cm from the +1 X 10^-6 charge and 5 cm from the +3 X 10^-6 charge, the electric field strength can be calculated as:

E = (9x10^9 Nm^2/C^2) * (1 X 10^-6 C + 3 X 10^-6 C) / (0.05 m)^2 = 2400 N/C

Since the two charges are of the same sign, the electric field at this point will be directed towards the +1 X 10^-6 charge, making it negative. This means that the electric field strength is pointing to the left.

In general, the electric field strength will decrease as we move away from the charges and will depend on the distance and the magnitude of the charges. At points further away from the charges, the electric field strength will approach zero.
 

1. What is the formula for calculating the electric field strength due to two point charges?

The formula for calculating the electric field strength due to two point charges is given by E = k*q/r^2, where E is the electric field strength, k is the Coulomb's constant (8.99 x 10^9 N*m^2/C^2), q is the magnitude of the charge, and r is the distance between the two charges.

2. How does the direction of the electric field due to two point charges depend on the charges' relative positions?

The direction of the electric field due to two point charges depends on the relative positions of the charges. If the two charges have the same sign, the electric field will point away from both charges. If the two charges have opposite signs, the electric field will point towards the positive charge and away from the negative charge.

3. Can the electric field due to two point charges cancel each other out?

Yes, the electric field due to two point charges can cancel each other out if the two charges have the same magnitude but opposite signs and are placed at equal distances from a point. This is known as an electric field equilibrium.

4. How does the electric field strength change as the distance between two charges increases?

The electric field strength decreases as the distance between two charges increases. This is because the electric field is inversely proportional to the square of the distance between the two charges. As the distance increases, the electric field spreads out over a larger area, resulting in a weaker field strength.

5. Is the electric field strength due to two point charges affected by the presence of other charges?

Yes, the electric field strength due to two point charges can be affected by the presence of other charges. This is because the electric field at a point is the vector sum of the electric fields due to all surrounding charges. Therefore, the presence of other charges can alter the direction and magnitude of the electric field at a point.

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