Assertion (A): Electrolyte are more conducting than metal.
Reason (R): Ions moves faster than electrons.
Assertion (A) is false; metals are generally far better conductors than electrolytes. Reason (R) is also false; electrons typically move faster than ions, and metals have a much higher density of charge carriers.
Assertion (A): Electric field is present in the vicinity of a current carrying wire.
Reason (R): The principle of conservation of charge is not followed, when charges are in motion.
Assertion (A) is true; an electric field is necessary to drive current through a wire. Reason (R) is false; the principle of conservation of charge is a fundamental law and holds true even when charges are in motion.
Assertion (A): As a wire is stretched to four times its length, its resistivity becomes four times, such that resistance also increases.
Reason (R): \( R = \frac{\rho A}{l} \) where symbols have their usual meaning.
Assertion (A) is false because resistivity is an intrinsic property of the material and does not change with stretching, only resistance changes. Reason (R) is false because the correct formula for resistance is \( R = \frac{\rho l}{A} \).