Assertion : If x and y are the distances also and y axes respectively then the dimension `(d^(3)y)/(dx^(3))` is `[M^(0)L^(-2)T^(0)]`
Reason : Dimensions of `overset(b) underset(a) int y dx ` is `[M^(0) L^(-2)T^(0)]`

Answer

(A) p, r (B) p, q, s (C) p, q (D) r, s

Explanation

`:'` Electric field due to an electric dipole at a point on equatorial line of dipole makes either `0^(@)` or `180^(@)` with the dipole moment of another dipole.
`:.` Torque on dipole `vec(tau)=vec(P)xxvec(E)` becomes zero
`( :' theta=0 or theta=180^(@))` Hence in column II.
[P] option is suit for every queries for column I. Electrostalic potential energy `(U)=-PE cos theta`
`theta=` Angle between moment & electric field.
[A] Here `theta=180^(@) :. U=-PE cos 180^(@)=PE`(+ve)
[B] Here `theta=0^(@) :. U=-PE cos theta=-PE` (-ve)
`[C] & [D] : theta lt 90^(@) :. U=` -v