250+ TOP MCQs on Projection of Straight Lines and Answers

Civil Engineering Drawing Multiple Choice Questions on “Projection of Straight Lines”.

1. A straight line is the ___________ distance between two points.
a) shortest
b) longest
c) half
d) infinite

Answer: a
Clarification: As we know lines are formed by points and shortest line which can be formed is the straight line between two points. Hence, the projections of a straight line may be drawn by joining the respective projections of its ends which are points.

2. A line is a geometric primitive that has no ____________
a) length
b) point
c) direction
d) thickness

Answer: d
Clarification: A point has no length or width. It has no thickness. Point is a mark of position. A point specifies the exact location. Point is denoted by a dot (.) and is named by an alphabet. Line is composed of infinite points and so here it can be said that a line also does not have thickness.

3. A line may not be __________
a) parallel to both the planes
b) parallel to one plane and perpendicular to the other
c) parallel to one plane and inclined to the other
d) perpendicular to both the planes

Answer: d
Clarification: The question is asking about a single line and if a line is perpendicular to both the planes it will never be resembled as a line i.e. it can’t be a single line. If it becomes perpendicular to the planes it will become perpendicular to itself thus forming two lines, as the single to will itself make 90 angle it can’t be further called as a single line.

4. When a line is parallel to a plane, the projection of the line on to that plane will be its ______ length.
a) shortened
b) true
c) enlarged
d) point

5. When a line is parallel to one plane and inclined to the other, the projection of the line on the plane to which it is parallel will show its __________ length.
a) shortened
b) true
c) enlarged
d) false

6. When the Projection of a line is parallel to both HP and VP its length will be _______
a) shortened
b) false
c) enlarged
d) true

7. In a case when a line is perpendicular to HP & parallel to VP then what figure will be projected on HP?
a) Point
b) Line
c) Square
d) Inclined line

8. A line AB, 90 mm long is inclined at 30° to HP and parallel to VP. The line is 80 mm in front of VP. The lower end A is 30 mm above HP. The upper end B is 50 mm in front of the right PP. The right profile plane will show a _________ projection.
a) point
b) small
c) true
d) false

9. If the apparent and the true inclinations of a line with HP are equal, the line is ____________
a) parallel to horizontal plane
b) parallel to vertical plane
c) parallel to profile plane
d) inclined to both reference plane

Answer: b
Clarification: When the line is parallel to the vertical plane and perpendicular to HP then it will form a point projection on the HP and so the apparent and the true inclination will be same of the line as it will resemble a point projection.

10. If the front view of a line is parallel to the xy line, its perpendicular length can be ___________
a) front view
b) top view
c) side view
d) no front view

Answer: d
Clarification: Since in both these cases line will be parallel to both the planes and so no perpendicular will fall on any of them hence neither top nor front views will be formed.

11. The point at which the line intersects the VP, extended if necessary, is known as ____________
a) profile trace
b) horizontal trace
c) vertical trace
d) auxiliary trace

Answer: c
Clarification: If a line is parallel to any of the plane, it has no trace upon that plane. For example: If the line is parallel to horizontal plane then that line will not meet H.P and hence there will be no Horizontal Trace and only Vertical Trace.

12. If top view of a line is a point, its front view is ____________
a) parallel to xy line and of true length
b) parallel to xy line and of apparent length
c) perpendicular to xy line and of true length
d) perpendicular to xy line and of apparent length

Answer: c
Clarification: When the line is parallel to the vertical plane and perpendicular to HP then it will form a point projection on the HP and so the apparent and the true inclination will be same of the line as it will resemble a point projection.