The electric field in aregion is radially ourward with magnitude `E=Ar`. Find the charge contained in a sphere of radius a centred at the origin. Take `A=100 V m^(-2)` and `a=20.0 cm`.

Explanation

To find the charge contained in a sphere of radius \( a \) centered at the origin, where the electric field \( E \) is given by \( E = Ar \), we can use Gauss's Law. Here are the steps to solve the problem:

### Step 1: Understand the Electric Field
The electric field is given as \( E = Ar \), where \( A = 100 \, \text{V/m}^2 \) and \( r \) is the radial distance from the origin.

### Step 2: Set Up Gauss's Law
Gauss's Law states that:
\[
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