Question

An infinitely long thin straight wire has a uniform linear charge density of 1 by 3 kulam per metre then the magnitude of electric intensity at point 18 cm away

Answer 1

linear charge density of infinitely long straight wire , $\lambda$ = 1/3 C/m

separation of point of observation to infinitely long straight wire , r = 18cm = 0.18m

we know,

magnetic field due to infinitely long straight wire at r distance away from it is given by, $E=\frac{\lambda}{2\pi\epsilon_0r}$

= (1/3)/{2 × 3.14 × 8.85 × 10^-12 × 0.18} N/C

= 10¹²/(2 × 3 × 3.14 × 8.85 × 0.18) N/C

= 1/30 × 10¹² N/C

= 100/30 × 10^10 N/C

= 3.33 × 10^10 N/C

hence, electric field intensity at point 18cm away is 3.33 × 10^10 N/C