JEE Advanced 2014 Paper 2

Four charges Q1,Q2,Q3 and Q4 of same magnitude are fixed along the x axis at x=−2a,−a,+a and +2a , respectively. A positive charge q is placed on the positive y axis at a distance b > 0. Four options of the signs of these charges are given in List I. The direction of the forces on the charge q is given in List II. Match List I with List II and select the correct answer using the code given below the lists.

List I		List II
P.	Q1,Q2,Q3,Q4 all positive	1.	+x
Q.	Q1,Q2 positive; Q3,Q4 negative	2.	−x
R.	Q1,Q4 positive; Q2,Q3 negative	3.	+y
S.	Q1,Q3 positive; Q2,Q4 negative	4.	−y