Here part A as the forces between each pair of charges will

Here ,

part A) as the forces between each pair of charges will be equal in magnitude and oposite in direction

for the force on charge 1 to match with force on charge 2

as when placed on the line C , the force lines of charge 2 and 1 will match .

part B)

NOw , as the force due to charge 3 must be horizontal along D on charge 1 , and the force between 1 and 3 is attractive ,

the charge 3 must be placed at D

part C) as the forces on the charge 2 are smaller ,

the smaller force on charge 1 must be due to charge 2

Now , hence , the horizontal force on the charge 1 must be due to A ,

as both 1 and 2 are negative , force between them is repulsive

the charge 2 must be placed along H

Solution

Ans : PART A

Step 1: Option C is correct

Step 2: Justification:

Free body diagram(FBD) shows the forces. So to match FBD for q1 , q2 has to be placed at line c

Ans PART B

Step 1: Option D is correct

Step 2: Justification:

Free body diagram(FBD) shows the forces. So to have consistent FBD for q1 , q2 , we have to place q3 at line D

Ans PART C

Step 1: Option H is correct

Step 2: Justification:

Free body diagram(FBD) shows the forces. So to match FBD for q1 , q2 has to be placed at line H.

The argumnt given along the question papers reflect the situation well.

Ans D

Step 1: Option F is correct

Step 2: Justification:

Free body diagram(FBD) shows the forces. Here q1=+2e, q2=+e and q3=-2e

Forces on q1 shows a small repulsive force along D line. This must be due to chage q2=e

The other force on q1 is a large attractive force along F line. This must be due to q3.

So q3 is along F line.

Now if we place q3 along F line , we find the FBD of q2 is satisfied:

two forces- equal in magnitude and opposite in nature( one attractive and one repulsive) are present.
Repulsive force is due to q1 . Attractive force is due to q3. the direction of the forces are consistent

with the positions of q1, q2 & q3

So to match FBD for q1 ,and q2 , q3has to be placed at line F

Ans b

Ans a

Step 1: Option c is correct

Step 2: Justification:

Free body diagram(FBD) shows the forces. So to match FBD for q1 , q2 hase to be placed at line c

Ans b

Ans b

Ans b