A steady current flows in a metallic conductor of non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/area)Current and drift speedb)Current, electric field and drift velocityc)Speed onlyd)Current only.Correct answer is option 'D'. Can you explain this answer?

Question

Answer

Steady current implies current is uniform across the cross-section.

Since current is constant, current per unit area and hence drift velocity are not constant.

J = nevd = σE

The above relation shows that nothing apart from the current is constant.

Answer

Current does not depend on the area of the conductor; hence it remains a constant.
Current density is inversely a constant.
Current density is inversely proportional to area (i.e.,) J∝1/A electric field drift speed is also inversely proportional to area (i.e.,) E∝1/A,V_d∝1/A
Hence current is constant along the conductor.

Answer

Explanation:

Current:
- In a metallic conductor, the current is the flow of electric charge carriers (usually electrons) per unit time.
- In a steady current, the amount of charge passing through any cross-section of the conductor per unit time is constant.
- Therefore, the current remains constant along the length of the conductor.

Electric Field:
- In a metallic conductor with a steady current, the electric field inside the conductor is also constant.
- The electric field is responsible for driving the current flow in the conductor.

Drift Velocity:
- The drift velocity of charge carriers in a metallic conductor is the average velocity of the charge carriers as they move in response to an electric field.
- In a steady current, the drift velocity remains constant along the length of the conductor.
Therefore, in a metallic conductor with a non-uniform cross-section and a steady current flowing through it, the only quantity that remains constant along the length of the conductor is the current. The electric field and drift velocity may vary due to the non-uniform cross-section, but the current remains constant.

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