Statement-1: Upthurst on a solid block of iron when immersed in a lake will be less on the surface than on the bed of the lake.
Statement-2: On the surface of the lake density of water will be less than that at the bed and upthrust depends on the density of liquid.

Options

A. Statement-1, is true, Statement-2 is true, Statement-2 is correct explanation for statement-1
B. Statement-1 is true, statement-2 is true, statement-2 is NOT a correct explantion for statement-1
C. statement-1 is true, statement-2 is false
D. statement-1 is false statement-2 is true

Answer

To solve the given problem, we need to analyze both statements and determine their validity and relationship.

### Step 1: Understand Statement-1
Statement-1 claims that the upthrust (or buoyant force) on a solid block of iron when immersed in a lake will be less on the surface than on the bed of the lake.

**Explanation:**
- The upthrust (buoyant force) experienced by an object submerged in a fluid is given by Archimedes' principle, which states that the buoyant force is equal to the weight of the fluid displaced by the object.
- Mathematically, the buoyant force (F_b) can be expressed as:
\[ F_b = V \cdot \rho \cdot g \]
where \( V \) is the volume of the object, \( \rho \) is the density of the fluid, and \( g \) is the acceleration due to gravity.

### Step 2: Understand Statement-2
Statement-2 states that the density of water on the surface of the lake will be less than that at the bed, and that upthrust depends on the density of the liquid.

**Explanation:**
- In a lake, the pressure increases with depth due to the weight of the water above. Consequently, the density of water at the bottom of the lake is generally greater than that at the surface.
- Therefore, since the upthrust depends on the density of the liquid, the upthrust will be greater at the bottom of the lake where the density is higher.

### Step 3: Analyze the Relationship Between the Statements
- Since the density of water is less at the surface than at the bottom, the upthrust (buoyant force) on the solid block of iron will indeed be less at the surface compared to the bottom of the lake.
- Thus, Statement-1 is true, and Statement-2 provides a valid explanation for Statement-1.

### Conclusion
Both statements are true, and Statement-2 correctly explains Statement-1. Therefore, the answer is:

**Correct Answer: Option A (Both statements are true, and Statement-2 is the correct explanation of Statement-1).**

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