1
JEE Main 2021 (Online) 25th July Evening Shift
+4
-1
Two ideal electric dipoles A and B, having their dipole moment p1 and p2 respectively are placed on a plane with their centres at O as shown in the figure. At point C on the axis of dipole A, the resultant electric field is making an angle of 37$$^\circ$$ with the axis. The ratio of the dipole moment of A and B, $${{{p_1}} \over {{p_2}}}$$ is : (take $$\sin 37^\circ = {3 \over 5}$$)

A
$${3 \over 8}$$
B
$${3 \over 2}$$
C
$${2 \over 3}$$
D
$${4 \over 3}$$
2
JEE Main 2021 (Online) 22th July Evening Shift
+4
-1
An electric dipole is placed on x-axis in proximity to a line charge of linear charge density 3.0 $$\times$$ 10$$-$$6 C/m. Line charge is placed on z-axis and positive and negative charge of dipole is at a distance of 10 mm and 12 mm from the origin respectively. If total force of 4N is exerted on the dipole, find out the amount of positive or negative charge of the dipole.
A
0.485 mC
B
815.1 nC
C
8.8 $$\mu$$C
D
4.44 $$\mu$$C
3
JEE Main 2021 (Online) 20th July Morning Shift
+4
-1
A certain charge Q is divided into two parts q and (Q $$-$$ q). How should the charges Q and q be divided so that q and (Q $$-$$ q) placed at a certain distance apart experience maximum electrostatic repulsion?
A
Q = 2q
B
Q = 4q
C
Q = 3q
D
Q = $${q \over 2}$$
4
JEE Main 2021 (Online) 18th March Morning Shift
+4
-1
An oil drop of radius 2 mm with a density 3g cm$$-$$3 is held stationary under a constant electric field 3.55 $$\times$$ 105 V m$$-$$1 in the Millikan's oil drop experiment. What is the number of excess electrons that the oil drop will possess? (consider g = 9.81 m/s2)
A
48.8 $$\times$$ 1011
B
1.73 $$\times$$ 1010
C
17.3 $$\times$$ 1010
D
1.73 $$\times$$ 1012
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