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GATE CS 2023 · General Aptitude

Question 10

MCQ2 marksWrong answer: −2/3Medium (estimate)

Question

Which one of the options best describes the transformation of the 2-dimensional figure P to Q, and then to R, as shown?

P is a five-pointed star with one long point toward the upper right. Operation 1 turns P into Q, whose long point is toward the lower right. Operation 2 turns Q into R, whose long point is toward the upper right and which is the mirror image of Q in a horizontal line.
Choose one option
Official answer and solution
Official answer
A
From
Official GATE 2023 answer key

Solution

Track the orientation and chirality of the figure across Operation 1 and Operation 2.

Let us trace the orientation of figure P:

  1. Figure P has its prominent asymmetric apex pointing upwards. In figure Q, this apex points to the right. A rotation from pointing up to pointing right in the plane corresponds to a 90∘90^\circ clockwise rotation about an axis perpendicular to the plane. The chirality is preserved (it is a rigid rotation, not a reflection).

  2. In figure R, the figure Q is inverted vertically across a horizontal axis: what was pointing right remains pointing right, but features that were on top are now on the bottom. This transformation is a reflection across a horizontal line.

Therefore, Operation 1 is a clockwise rotation by 90∘90^\circ, and Operation 2 is a reflection along a horizontal line.

Final answer

Option (A)

Common trap

Confusing a horizontal reflection with a vertical reflection (reflection along a horizontal mirror line flips vertically).

The answer is the one in the official GATE answer key. The solution is this site's own explanation.

Source

Paper
GATE 2023 Computer Science and Information Technology (CS)
Question
10 of 65
Section
General Aptitude

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