Q. In the following four situations charged particles are at equal distance from the origin. Arrange them the magnitude of the net electric field at origin greatest first
A) $(i) > (ii) > (iii) > (iv)$
B) $(ii) > (i) > (iii) > (iv)$
C) $(i) > (iii) > (ii) > (iv)$
D) $(iv) > (iii) > (ii) > (i)$
Explanation
(c) If electric field due to charge $|q|$ at origin is $E$ then electric field due to charges $|2q|,\ |3q|,\ |4q|$ and $|5q|$ are respectively $2E,\ 3E,\ 4E$ and $5E$
$E_{(i)} = \sqrt{(5E)^{2} + (5E)^{2}} = 5\sqrt{2}E,$
$E_{(ii)} = \sqrt{(3E)^{2} + (3E)^{2}} = 3\sqrt{2}E,$
$E_{(iii)} = 4E + 2E = 6E$ and $E_{(iv)} = 3E + E = 4E$
$\Rightarrow E_{(i)} > E_{(iii)} > E_{(ii)} > E_{(iv)}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.