NECO 2000 Physics · Question 39

A block of a substance X will sink in a liquid V but float liquid Z. Which of the following statements is NOT…

Question

A block of a substance X will sink in a liquid V but float liquid Z. Which of the following statements is NOT correct about the densities of the three substances?

A.Density of liquid Z is greater than that of X
B.Density of liquid V is less than that of liquid X
C.Density of liquid Y is less than that of liquid Z
D.Liquid Z has the greatest density of all the three substances.
E.If liquids V and Z do not mix, liquid Z will float on liquid V.

Answer: E. If liquids V and Z do not mix, liquid Z will float on liquid V.

Explanation written with AI and checked against the answer key

Analyze the question: X sinks in V, so density of X > density of V. X floats in Z, so density of X < density of Z. Combining these: ρV < ρX < ρZ.

(The question mentions "liquid Y" in option C, which is almost certainly a typo for V. I'll read it that way.)

Concept: An object sinks in a liquid less dense than itself and floats in a liquid denser than itself. If two liquids don't mix, the denser one sinks below the less dense one.

Check each option:

A. ρZ > ρX. True, since X floats in Z.
B. ρV < ρX. True, since X sinks in V.
C. ρV (read as "Y") < ρZ. True, since ρV < ρX < ρZ.
D. Z has the greatest density of the three. True, since ρZ > ρX > ρV.
E. If V and Z do not mix, Z floats on V. This is false. Z is denser than V, so Z would sink below V, and V would float on Z.

Answer: The statement that is NOT correct is E.

Tip: For "NOT correct" questions, work out the density order first (here ρV < ρX < ρZ), then test each option against it. Remember that the denser liquid always goes to the bottom.

AI can make mistakes. Report anything that looks wrong.