A copper conductor is in the shape of a cylindrical shell of length 20 cm and inner and outer diameter 1 cm and 3 cm. A potential difference 200 V is applied between the flat surfaces of the conductor. The current density in it is `10A//m^2` . The value of x is ________

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Identify the given values
- Length of the cylindrical shell, \( L = 20 \, \text{cm} = 0.2 \, \text{m} \)
- Inner diameter, \( d_i = 1 \, \text{cm} = 0.01 \, \text{m} \) (inner radius \( r_i = 0.005 \, \text{m} \))
- Outer diameter, \( d_o = 3 \, \text{cm} = 0.03 \, \text{m} \) (outer radius \( r_o = 0.015 \, \text{m} \))
- Potential difference, \( V = 200 \, \text{V} \)
- Resistivity of copper, \( \rho = 10^{-8} \, \Omega \cdot \text{m} \)
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