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1. Electric Charges and Fields
easy
If atmospheric electric field is approximately $150 \,volt / m$ and radius of the earth is $6400 \,km$, then the total charge on the earth's surface is .......... coulomb
A
$6.8 \times 10^5$
B
$6.8 \times 10^6$
C
$6.8 \times 10^4$
D
$6.8 \times 10^9$
Solution
(a)
$E=150 \,V / m$
$R=6400 \,km$
Using Gauss' Law
$\Rightarrow E A=\frac{q}{\varepsilon_0}$
$\Rightarrow 150\left(4 \pi\left(6400 \times 10^3\right)^2\right)=\frac{q}{\varepsilon_0}$
$q=150 \times 4 \pi \times\left(6400 \times 10^3\right)^2 \times 8.854 \times 10^{-12}$
$q=6.8 \times 10^5 \,C$
Standard 12
Physics
