An infinite line charge produces a field of 9×104N/C at a distance of 2 cm. Calculate the linear charge density.
Step 1: Electric field due to infinite line charge
Electric field due to infinite line charge is given by:
E=λ2π∈0d
⇒λ=2π∈0E d ....(1)
Where λ is the linear charge density and d is the perpendicular distance of point from the infinite line charge.
Step 2: Substituting the values
∵14π∈0=9×109Nm2C−2
⇒2π∈0=118×109Nm2C−2
From Eq (1): λ=1×9×104 NC−1×0.02m18×109 Nm2C−2=10−7 Cm−1