Step 1: Understanding the relationship.
According to Charles' law, for a fixed mass of gas at constant pressure, the volume of the gas is directly proportional to the temperature (in Kelvin). This can be written as:
\[
\frac{V_1}{T_1} = \frac{V_2}{T_2}
\]
Where \(V_1\) and \(T_1\) are the initial volume and temperature, and \(V_2\) and \(T_2\) are the final volume and temperature.
Step 2: Applying the values.
Given that the initial temperature is \(x\) K, the initial volume is 2 dm\(^3\), and the final temperature is \(10x\) K, we can calculate the final volume \(V_2\):
\[
\frac{2 \, \text{dm}^3}{x} = \frac{V_2}{10x}
\]
Solving for \(V_2\):
\[
V_2 = 20 \, \text{dm}^3
\]
Step 3: Conclusion.
The correct answer is (A) 20 dm\(^3\). The volume increases by a factor of 10 when the temperature increases from \(x\) K to \(10x\) K.