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GATE 2023 CS – Question 5

General Aptitude · Spatial Aptitude: Spatial Reasoning and Visualization · 1 mark · Multiple choice

Looking at the surface of a smooth 3-dimensional object from the outside, which one of the following options is TRUE?

  1. The surface of the object must be concave everywhere.
  2. The surface of the object must be convex everywhere.
  3. The surface of the object may be concave in some places and convex in other places.
  4. The object can have edges, but no corners.

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Show answer and explanation

Correct answer: (C) The surface of the object may be concave in some places and convex in other places.

Explanation

A smooth surface can curve either way in different regions, so it may be concave in some places and convex in others. Smooth objects have neither edges nor corners.