AP EAMCET2009PhysicsElectrostatics
An infinitely long thin straight wire has uniform linear charge density of 1 3 Cm ⁻¹ . Then, the magnitude of the electric intensity at a point 18 ~cm away is (given ₀=8.8 10⁻¹² C ^2 Nm ⁻² )
Options
- A0.33 10¹¹ NC ⁻¹
- B3 10¹¹ NC ⁻¹
- C0.66 10¹¹ NC ⁻¹
- D1.32 10¹¹ NC ⁻¹
Correct answer
C. 0.66 10¹¹ NC ⁻¹
Step-by-step solution
Charge density of long wire aligned & = 1 3 C - m and r & =18 10⁻² ~m aligned From Gauss theorem gathered E d S = q ₀ E d S= q ₀ gathered or E 2 r l= q ₀ or E= q 2 ₀ r l = q / l 2 ₀ r aligned & = 2 2 ₀ r 2 = 2 4 ₀ r & =9 10^9 1 3 2 1 18 10⁻² & = 1 3 10¹¹=0.33 10¹¹ & =0.33 10¹¹ NC ⁻¹ aligned