NEET Physics Question - Current Electricity - Relation between Current and Drift Velocity

Assertion (A): When constant current is passing through a conductor of variable area of cross section, electric field inside conductor is inversely proportional to cross sectional area.

Reason (R): Microscopic form of Ohm's law is \( \vec{E} = \rho \vec{J} \), where \( \vec{E} \) stands for electric field, \( \rho \) stands for resistivity and \( \vec{J} \) stands for current density.

(1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)

(2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(3) (A) is true but (R) is false

(4) Both (A) and (R) are false

Solution:

Assertion (A) is true because \( I = JA \) and \( E = \rho J \) imply \( E = \frac{\rho I}{A} \). Reason (R) is true as it's the microscopic form of Ohm's law. Reason correctly explains assertion.

Rankers Physics

Electric field, current and resistivity

Solution:

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