Polar coordinates of an electric field

In summary, the conversation discusses finding the direction of the electric field using polar coordinates for a system of three charges. The attempt at a solution involves calculating the electric field components and finding the angle, but the result is incorrect. The conversation ends with a request for help and a clarification on the location of the electric field.
  • #1
netteo
6
0

Homework Statement



Three charges are arranged as presented below. Q1= 5.00E-9C, Q2= 6.00E-9C and Q3= -7.00E-9C.

http://img15.imageshack.us/img15/9250/physicskf.png

D) Find the direction of the above electric field using the polar coordinate system 0°< θ <360°

Homework Equations



tan θ = o/a

The Attempt at a Solution



I found my

E1 = 500
E2 = 5400
E3 = -700

Ex = 500 cos 18.4° + (-700) = -225.6
Ey = 500 sin 18.4° + 5400 = 5557.8

But the angle that I got was incorrect which was 24.63°.

Help anyone?
 
Last edited by a moderator:
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  • #2
netteo said:

Homework Statement



Three charges are arranged as presented below. Q1= 5.00E-9C, Q2= 6.00E-9C and Q3= -7.00E-9C.

http://img15.imageshack.us/img15/9250/physicskf.png

D) Find the direction of the above electric field using the polar coordinate system 0°< θ <360°

Homework Equations



tan θ = o/a

The Attempt at a Solution



I found my

E1 = 500
E2 = 5400
E3 = -700

Ex = 500 cos 18.4° + (-700) = -225.6
Ey = 500 sin 18.4° + 5400 = 5557.8

But the angle that I got was incorrect which was 24.63°.

Help anyone?
You are finding the Electris Field at what location?
 
Last edited by a moderator:
  • #3
Oops, sorry about that. Point P (0.3m,-0.1m)
 
  • #4
Review the signs of your components .
 
  • #5


I would first commend the student for their attempt at finding the direction of the electric field using the polar coordinate system. However, I would also suggest that they double check their calculations and make sure they are using the correct units for the electric field. It is also important to note that the angle given (24.63°) may not be incorrect, as it is possible that the charges are not perfectly aligned with the polar axes. In this case, it would be helpful to include a diagram or a more detailed explanation of the problem to better understand the situation. Additionally, I would recommend using vector addition to find the net electric field at a specific point instead of calculating the components separately. This would give a more accurate and comprehensive understanding of the electric field at that point.
 

1. What are polar coordinates?

Polar coordinates are a way of representing points in a two-dimensional space using a distance from the origin and an angle from a reference direction. In the context of an electric field, polar coordinates are used to describe the strength and direction of the electric field at a particular point.

2. How are polar coordinates used to describe an electric field?

In an electric field, polar coordinates are used to specify the magnitude and direction of the electric field at a specific point. The distance from the origin represents the strength of the electric field, while the angle from a reference direction (usually the positive x-axis) indicates the direction of the field vector.

3. What is the difference between polar coordinates and Cartesian coordinates?

While both polar coordinates and Cartesian coordinates are used to represent points in a two-dimensional space, they use different methods to describe the position of a point. In polar coordinates, the position is described using a distance and an angle, whereas in Cartesian coordinates, the position is described using x and y coordinates on a grid.

4. How do you convert between polar and Cartesian coordinates?

To convert from polar coordinates to Cartesian coordinates, you can use the following equations:
x = r*cos(θ)
y = r*sin(θ)
where r is the distance from the origin and θ is the angle from a reference direction. To convert from Cartesian coordinates to polar coordinates, you can use the equations:
r = √(x^2 + y^2)
θ = tan^-1(y/x)
where x and y are the Cartesian coordinates of the point.

5. How are polar coordinates used in electromagnetic theory?

In electromagnetic theory, polar coordinates are used to describe the electric field and magnetic field at a particular point. They help to determine the direction and strength of these fields, which are crucial in understanding the behavior of electromagnetic waves and the interaction between charged particles.

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