A: If a spring block system, oscillating in a vertical plane is made to oscillate on a horizontal surface, the time period will remain same.
R: The time period of spring block system does not depend on g.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to analyze the assertion (A) and the reason (R) provided:

**Assertion (A)**: If a spring block system oscillating in a vertical plane is made to oscillate on a horizontal surface, the time period will remain the same.

**Reason (R)**: The time period of a spring block system does not depend on g (acceleration due to gravity).

### Step-by-Step Solution:

1. **Understanding the Time Period of a Spring Block System**:
The time period \( T \) of a spring block system is given by the formula:
\[ T = 2\pi \sqrt{\frac{m}{k}} \]
where \( m \) is the mass of the block and \( k \) is the spring constant.

2. **Analyzing the Effect of Gravity**:
The formula for the time period of a simple pendulum is:
\[ T = 2\pi \sqrt{\frac{l}{g}} \]
Here, \( l \) is the length of the pendulum and \( g \) is the acceleration due to gravity. Notice that this formula is dependent on \( g \).

3. **Comparing Oscillation in Vertical and Horizontal Planes**:
When the spring block system is oscillating in a vertical plane, the effective force acting on the mass due to gravity affects the equilibrium position of the spring. However, the time period of oscillation is determined by the mass and spring constant, not by gravity.

4. **Equilibrium Position**:
When the spring block system is moved to oscillate on a horizontal surface, the effect of gravity is not directly influencing the oscillation in terms of time period. The equilibrium position changes, but the ratio \( \frac{l}{g} \) remains constant because as \( g \) changes, the equilibrium position \( l \) also adjusts accordingly.

5. **Conclusion**:
Since the time period of the spring block system does not depend on \( g \), we conclude that:
- The assertion (A) is true.
- The reason (R) is also true and correctly explains the assertion.

Thus, the final answer is that both the assertion and reason are correct, and the reason is a correct explanation of the assertion.

### Final Answer:
Both assertion and reason are correct, and the reason is a correct explanation of the assertion.

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