JEE MAIN - Physics (2020 - 9th January Morning Slot - No. 8)
An electric dipole of moment
$$\overrightarrow p = \left( { - \widehat i - 3\widehat j + 2\widehat k} \right) \times {10^{ - 29}} $$ C.m is
at the origin (0, 0, 0). The electric field due to this dipole at
$$\overrightarrow r = + \widehat i + 3\widehat j + 5\widehat k$$ (note that $$\overrightarrow r .\overrightarrow p = 0$$ ) is parallel to :
$$\overrightarrow p = \left( { - \widehat i - 3\widehat j + 2\widehat k} \right) \times {10^{ - 29}} $$ C.m is
at the origin (0, 0, 0). The electric field due to this dipole at
$$\overrightarrow r = + \widehat i + 3\widehat j + 5\widehat k$$ (note that $$\overrightarrow r .\overrightarrow p = 0$$ ) is parallel to :
$$\left( { + \widehat i + 3\widehat j - 2\widehat k} \right)$$
$$\left( { + \widehat i - 3\widehat j - 2\widehat k} \right)$$
$$\left( { - \widehat i + 3\widehat j - 2\widehat k} \right)$$
$$\left( { - \widehat i - 3\widehat j + 2\widehat k} \right)$$
توضیح
Since $$\overrightarrow r $$
and $$\overrightarrow p $$
are perpendicular to each other
therefore point lies on the equitorial plane.
Therefore electric field at the point will be
antiparallel to the dipole moment.
$$ \therefore $$ $$\overrightarrow E || - \overrightarrow p $$
$$ \Rightarrow $$ $$\overrightarrow E ||\left( {\widehat i + 3\widehat j - 2\widehat k} \right)$$
$$ \therefore $$ $$\overrightarrow E || - \overrightarrow p $$
$$ \Rightarrow $$ $$\overrightarrow E ||\left( {\widehat i + 3\widehat j - 2\widehat k} \right)$$