Assertion–Reason (Why do icebergs float?) Assertion (A): Icebergs, a solid form of water, float on seawater. Reason (R1): About two-thirds of an iceberg is below water and one-third above the surface. Reason (R2): Icebergs are heavier than water and displace seawater, which makes them float. Decide which reason(s) truly explain A.
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AIf only reason 1 (R1) and not reason 2 (R2) is the reason for the assertion (A).
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BIf only reason 2 (R2) and not reason 1 (R1) is the reason for the assertion (A).
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CIf both (R1) and (R2) are reasons for the assertion (A).
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DIf neither (R1) nor (R2) is the reason for the assertion (A).
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ENone of these
Answer
Correct Answer: If neither (R1) nor (R2) is the reason for the assertion (A).
Explanation
Introduction / Context:Floating is governed by relative density and buoyancy, not by post-hoc descriptions of how much is submerged. This question probes correct physical reasoning.
Given Data / Assumptions:
- A: Icebergs float.
- R1: About two-thirds submerged and one-third above (a description/observation, not a cause).
- R2: “Icebergs are heavier than water” (factually incorrect; ice is less dense than liquid water).
Concept / Approach:Buoyancy states that an object floats when its average density is less than the fluid’s density. Sea ice/icebergs (density ~0.92 g/cm^3) are less dense than seawater (~1.025 g/cm^3), hence they float. R1 is an effect/ratio of buoyant equilibrium, not the reason. R2 contradicts the density condition for floating.
Step-by-Step Solution:
1) Evaluate R1: It reports the floating geometry but does not explain why floating occurs.2) Evaluate R2: If an iceberg were heavier (denser) than water, it would sink; therefore R2 is false as a reason.3) Neither R1 nor R2 serves as the causal explanation.Verification / Alternative check:The correct reason would be “Ice is less dense than seawater; buoyant force balances weight at partial submergence.”
Why Other Options Are Wrong:A/B/C wrongly confer causal status to a description or a false statement.
Common Pitfalls:Confusing observed proportions (how much shows above water) with the underlying cause (density difference).
Final Answer:If neither (R1) nor (R2) is the reason for the assertion (A).