Question

A plane surface may be positioned in space with reference to the three principal planes of projection in any of the following positions, which one is false?

(a) Parallel to one of the principal planes and perpendicular to the other two

(b) Perpendicular to one of the principal planes and inclined to the other two

(c) Parallel to both the planes

(d) Inclined to all the three principal planes

The question was posed to me in a job interview.

My question is from Projections of Planes topic in section Orthographic Projection, Projections of Lines, Planes and Solids of Civil Engineering Drawing

Answer 1

The correct answer is (c) Parallel to both the planes

Explanation: Planes may be divided into two main types: Perpendicular planes and Oblique planes.

And this perpendicular plane is further divided into three parts- a) Parallel to one of the principal planes and perpendicular to the other two. b) Perpendicular to one of the principal planes and inclined to the other two. c) Inclined to all the three principal planes.