NEET 2023 Phase 1 · PhysicsDrift velocityPrevious Year Question
A copper wire of radius 1 mm contains 10 free electrons per m. The drift velocity for a 10 A current is (e = 1.610 C):
Answer: (D) (6.25/)10 m s. \textbf{Answer:} (4) per official key [computation gives option (2)] \textbf{Solution:} v_d = I/(nAe), A = r = 10 m.
- A.6.25/ m s
- B.(6.2510)/ m s
- C.(6.2510)/ m s
- D.(6.25/)10 m s✓
Correct Answer
(D) (6.25/)10 m s
Solution & Explanation
\textbf{Answer:} (4) per official key [computation gives option (2)] \textbf{Solution:} v_d = I/(nAe), A = r = 10 m. v_d = 10/(10101.610) = (6.2510)/ m s. NOTE: this matches option (2); the official NEET key marks (4) — a known discrepancy, reproduced as-is.
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