NEET2022Physics-Current Electricity
NEET 2022 Physics Current Density MCQ Question
Type: MCQ-numerical-Hard-Class 12
A copper wire of length 10 m and radius (10²√π) m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10 (V/m) is:
A
10³ A/m²
B
10⁵ A/m²
C
10⁴ A/m²
D
10⁶ A/m²
Correct Answer
Option B
Detailed Explanation
Current density J = σE, where σ is the conductivity. Given resistance R, length L, and radius r, calculate σ and then J.
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