Urgent help required with electric fields question

How on EARTH do you do this?

Ok so first let us start with the definition of electric field strength - it is the force felt per unit mass in an electric field BY A POSITIVE TEST CHARGE.

At P the horizontal force (AP) felt by a positive test charge is unaffected by A initially.

So you can ignore A for this part and just work out the electric field strength from B! Hope that helps for part 1

I am very confused about what you mean.

Reply 2

tallulabellm

Original post by ayyboss

I am very confused about what you mean.

Okay bro would be great if you could tell me what is confusing you in the question.

Reply 3

tallulabellm

Original post by ayyboss

I am very confused about what you mean.

OH MAN, I can see why you thought it was confusing ! I was talking about the wrong directions as I read part a and b mixed up! so sorry dude. Will do it tomorrow when I'm not in bed xD

Reply 4

username2982648

Original post by Assmaster2

OH MAN, I can see why you thought it was confusing ! I was talking about the wrong directions as I read part a and b mixed up! so sorry dude. Will do it tomorrow when I'm not in bed xD

If possible, would you be able to show your working for each part? I don't understand this question at all :\

Reply 5

Eimmanuel

Study Forum Helper

Original post by LeCroissant

If possible, would you be able to show your working for each part? I don't understand this question at all :\

I “coloured” the positive and negative charge.

(i)
The positive charge would produce an electric field at P and the direction is shown in red.
The electric field at P due A would be

|E_A| = \dfrac{k Q_A}{r_{AP}^2}

-------(1)

where k is 9.0 × 10⁹ N m² C^-².

(ii)
The negative charge would produce an electric field at P with the direction shown in blue.
The electric field at P due B would be

|E_B| = \dfrac{k Q_B}{r_{PB}^2}

-------(2)

See the following website and employ the method to find the resultant field.
http://www.phyley.com/find-resultant-force

Remember to convert the separation in mm to m before you substitute them into the eqn (1) and (2).