Electrostatics

JEE Main level, single correct, medium

240 of 311

Question 240 of 311

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Net dipole moment of a polar linear isotropic dielectric substance is not zero even in the absence of an external electric field.
Reason (R) : In absence of an external electric field, the different permanent dipoles of a polar dielectric substance are oriented in random directions.
In the light of the above statements, choose the most appropriate answer from the options given below :

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Answer: (D) (A) is not correct but (R)(\mathrm{R}) is correct

A : Since polar dielectrics are randomly oriental P→net=0→\overrightarrow{\mathrm{P}}_{\mathrm{net}}=\overrightarrow{0}.
R : If E→\overrightarrow{\mathrm{E}} is absent, polar dielectric remain polar \& are randomly oriented.

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