Electric field in a region of space is radially outward from origin and varies with distance 'r' from origin as E = kr. Find the charge enclosed in a sphere of radius 'a' centred at origin.

Explanation

To find the charge enclosed in a sphere of radius 'a' centered at the origin, given that the electric field \( E \) varies with distance \( r \) from the origin as \( E = kr \), we can use Gauss's law. Here’s a step-by-step solution:

### Step 1: Understand the Electric Field
The electric field is given as:
\[ E = kr \]
where \( k \) is a constant and \( r \) is the distance from the origin. At a distance \( r = a \), the electric field becomes:
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