Step 1: Analyzing the System
The system consists of two blocks, each of mass \( m = 3 \, {kg} \), connected by two springs with spring constant \( K = 9 \, {N/m} \). The springs are arranged in parallel between the two masses. We need to find the time period of oscillation of the system.
Step 2: Finding the Effective Spring Constant for the System
Since the springs are connected in parallel, the effective spring constant \( K_{{eff}} \) is the sum of the individual spring constants:
\[
K_{{eff}} = K + K = 9 + 9 = 18 \, {N/m}
\]
Step 3: Time Period of the System
For a mass-spring system, the time period \( T \) of oscillation is given by the formula:
\[
T = 2 \pi \sqrt{\frac{m_{{eff}}}{K_{{eff}}}}
\]
Where:
- \( m_{{eff}} \) is the effective mass of the system, which is the sum of the two masses:
\[
m_{{eff}} = 3 + 3 = 6 \, {kg}
\]
- \( K_{{eff}} = 18 \, {N/m} \) is the effective spring constant.
Substitute the values into the formula for the time period:
\[
T = 2 \pi \sqrt{\frac{6}{18}} = 2 \pi \sqrt{\frac{1}{3}} = 2 \pi \times \frac{1}{\sqrt{3}} \approx 2 \pi \times 0.577 \approx 1.63 \, {s}
\]
Step 4: Conclusion
Thus, the time period of oscillation for the spring-block system is approximately \( \boxed{1.63 \, {s}} \).