Which set of lead grades has a grade out of sequence?
A) H, HB, B, 3B
B) 7B, H, F, 3H
C) 6B, B, H, 4H
D) 9H, HB, B, 2B
ANS: B
- Which type of line is part of a dimension?
A) break lines
B) phantom lines
C) extension lines
D) cutting plane lines
ANS: C - Which type of line is particular to section drawings?
A) break lines
B) phantom lines
C) extension lines
D) cutting plane lines
ANS: D
The Correct Answer and Explanation is :
Question 1: Which set of lead grades has a grade out of sequence?
Given Answer: B) 7B, H, F, 3H
Correct Answer: B) 7B, H, F, 3H
Explanation:
Pencil lead grades follow a specific sequence based on hardness and darkness. The scale typically runs from 9H (hardest/lightest) to 9B (softest/darkest), with HB and F in between.
The correct order is:
- H series (Hard): 9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H
- Mid-range: F, HB
- B series (Soft): B, 2B, 3B, 4B, 5B, 6B, 7B, 8B, 9B
In option B (7B, H, F, 3H), the numbers are not in sequential order. 7B is very soft, while H and 3H are hard, and F is in between HB and H. This disrupts the proper transition of hardness. Therefore, this option has an out-of-sequence grade.
Question 2: Which type of line is part of a dimension?
Given Answer: C) Extension lines
Correct Answer: C) Extension lines
Explanation:
Dimensioning lines are essential in technical drawing, as they provide measurements. The types of lines used in dimensioning include:
- Dimension lines – Indicate the length of an object.
- Extension lines – Extend from the object to define the dimension limits.
- Leader lines – Point to a specific feature with a note or measurement.
Extension lines extend from the feature being measured without touching it, making them integral to dimensioning.
Question 3: Which type of line is particular to section drawings?
Given Answer: D) Cutting plane lines
Correct Answer: D) Cutting plane lines
Explanation:
Section drawings are used to show internal features of an object by “cutting” through it. Several lines are used in section views:
- Cutting Plane Lines – Show where the object is “cut.”
- Section Lines (Hatching) – Indicate the cut surfaces.
- Phantom Lines – Show motion or repeated elements.
Since cutting plane lines define the location and direction of the cut in a section view, they are unique to section drawings.