# How do I check if it is a positive charge or negative charge?

• CKaiL
In summary, the electric field at the origin due to charges q1 and q2 is zero, so the polarity of Ex due to q1 has to be the opposite, and q2 does not produce an x component of the E field at the origin.
CKaiL

## The Attempt at a Solution

[/B]
The electric field at the origin O, due to charges Q, q1 and q2, is equal to zero
Hence , EQ = Eq1
q = cos30 x 300 x10^-9/4 * 1.8^2 = 210 x10^-9 C

So I am able to find out that q = 210 x 10^-9 C and that mean that B and C cannot be the answer which left me with A and D.

How do I check if it is a positive charge or negative charge?

Last edited by a moderator:
CKaiL said:

## The Attempt at a Solution

The electric field at the origin O, due to charges Q, q1 and q2, is equal to zero
Hence , EQ = Eq1
q = cos30 x 300 x10^-9/4 * 1.8^2 = 210 x10^-9 C

So I am able to find out that q = 210 x 10^-9 C and that mean that B and C cannot be the answer which left me with A and D.

How do I check if it is a positive charge or negative charge?
[/B]
The x component at the origin due to Q is what polarity? So the polarity of Ex due to q1 has to be the opposite, right? So what then does the polarity of q1 have to be?

Why does it has to be opposite for the polarity of Ex due to q1?

CKaiL said:
Why does it has to be opposite for the polarity of Ex due to q1?
because the net E field at the origin is zero so q1 has to cancel out the x component of Q.

What about the q2 at the y component?

CKaiL said:
What about the q2 at the y component?
q2 does not produce an x compnent of the E field at the origin. You are summing x components of E at the origin.

By the way, you can also solve this problem with summing y components of E = 0 at the origin. I suggest you do it for increased understanding.

## 1. How do I determine if an object has a positive or negative charge?

The easiest way to check if an object has a positive or negative charge is to use a charge detector. This device can detect the presence of electric charges and indicate whether the charge is positive or negative.

## 2. Can I use my hands to check for a charge?

No, it is not recommended to use your hands to check for a charge as this can be dangerous. It is best to use a specialized tool, such as a charge detector, to accurately determine the charge of an object.

## 3. How can I tell the difference between positive and negative charges?

A positive charge will repel a positively charged object and attract a negatively charged object. On the other hand, a negative charge will repel a negatively charged object and attract a positively charged object. You can also use a charge detector to confirm the charge of an object.

## 4. What causes an object to have a positive or negative charge?

An object can acquire a positive or negative charge through the gain or loss of electrons. When an object gains electrons, it becomes negatively charged, and when it loses electrons, it becomes positively charged.

## 5. Can an object have both a positive and negative charge?

No, an object cannot have both a positive and negative charge at the same time. However, an object can have regions of positive and negative charges, which is known as a dipole. This occurs when the charges within the object are not evenly distributed.

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