NEET2026PhysicsChapterActual
A uniform nichrome wire of length 4.0 m and cross-sectional area 0.2 mm ^2 has an electrical resistance of 5.0 . If an electric field of 1.5 V m ⁻¹ is established along its length, the current density in the wire is:
Options
- A1.5 10^6 A m ⁻²
- B6 10^4 A m ⁻²
- C6 10^6 A m ⁻²
- D2.4 10⁻⁷ A m ⁻²
Correct answer
C. 6 10^6 A m ⁻²
Step-by-step solution
Given l = 4.0 m , A = 0.2 mm ^2 = 2 10⁻⁷ m ^2 , R = 5.0 , and E = 1.5 V m ⁻¹ . The potential difference across the wire is: V = E l = 1.5 4.0 = 6.0 V The current flowing through the wire is: I = V R = 6.0 5.0 = 1.2 A The current density J is given by: J = I A = 1.2 2 10⁻⁷ = 6 10^6 A m ⁻² Answer: 6 10^6 A m ⁻²