Engineering Drawing MCQ Quiz - Objective Question with Answer for Engineering Drawing - Download Free PDF

Explanation:

Engineering drawing lines:

• Continuous thin lines: these thin continuous lines could be a straight or curved lines. these lines are used for various representations like projection lines, hatching lines, construction lines, short lines, short center lines, measurement lines, dimension lines, intersection lines, lead lines, backside lines.

Additional Information

Concept:

In modern engineering, the materials used have become so numerous and diversified that it is not possible to prescribe different hatching lines for different materials. 

Following are some conventional representation which is used for the  materials:

Explanation:

Mini drafter

• It is an important device used for making drawings quickly & accurately.
• This instrument has a combination of T-square, set-square, protractor, and scales, it helps to draw the drawings at a faster rate. 
• They come in different sizes and a pattern called ‘Pantagraph’ type.
• It is fitted on the top left side, edge of the drafting board, mounted on an adjustable frame or table.

Erasing shield:

• When, on a drawing, if a part of a line or some lines among many other lines needs to be erased or modified, in the normal way of erasing will damage the other nearby lines.
• In such a situation an erasing shield is effectively useful.
• It is a thin metallic sheet having small openings of different sizes and shapes.
• A suitable opening is aligned to the line to be erased and the line is removed by the eraser.

Explanation:

Dimensions in "mm" for different sizes of drawing sheets are as follows:

Explanation:

Projection Systems:

1. First angle projection system  2. Third angle projection system

• Both third angle and first-angle projection display the standard three orthographic views of a part or assembly.

• The key difference between third angle and first angle is the layout of the part on the sheet.

​1. First angle projection system:​

• In first angle projection, top view is located below the front view.

​2.  Third angle projection system:

• In Third angle projection top view is located above the front view.

Additional Information

Orthographic Projection:

Orthographic Projections is a technical drawing in which different views of an object are projected on different reference planes observing perpendicular to respective reference plane.

• Horizontal Plane (HP)
• Vertical Plane (VP)

• Side or Profile Plane (PP)

• Front View (FV) – Projected on VP
• Top View (TV) – Projected on HP
• Side View (SV) – Projected on PP
   

The correct answer is 120-degree.

Key Points

• Draw horizontal and vertical lines to represent an isometric object.
• While horizontal lines are drawn at a 30-degree angle to the horizontal plane, vertical lines remain vertical.
• All three axes must be at a 120-degree angle from one another. Now, if you adhere to rule number 1, this is accomplished automatically.
• An object's three faces are all equally foreshortened in the isometric projection.
• Any mechanical drawing or system is typically explained with an isometric drawing.
• It can be found on instructions for model kits like Lego, Gundam, and others, as well as mechanical infographics. 

Internal Angle and External Angle can be seen in the diagram below.

Explanation:

Scales are used to make drawings of the objects to the proportionate size desired. 

A scale is defined as the ratio of the linear dimensions of element of the object as represented in drawing to the actual dimensions of the same element of the object itself.

In this case, the relation between the dimension on the drawing and the actual dimension of the object is mentioned numerically in the style as 10 mm = 5m, etc.

BIS recommends eight set-scales in plastic/cardboard with designations MI, M2 and so on as shown in table.

Explanation:

Perspective View: These are most realistic drawings. Our eyes see objects in perspective. There are three types of perspective projections: one, two- and three-point perspective projections.

Oblique Projection: These are least realistic. Only one or two faces in oblique projections have true shape and size. There are three types of oblique projections: cabinet, cavalier and general.

Axonometric Projection: These are more realistic than oblique. Horizontal edges of an object in axonometric projections are parallel to each other and inclined to the plane. There are three types of axonometric projections: isometric, dimetric and trimetric.

Isometric (meaning “equal measure”) is a type of parallel (axonometric) projection, where the X and Z axes are inclined to the horizontal plane at the angle of 30⁰. The angle between axonometric axes equals 120⁰.

If a line is parallel to V. P. and inclined to H. P., its top view will be of smaller dimension.

If a line is parallel to H. P. and inclined to V. P., it's front view will be of smaller dimension.

a’b’ = AB cosθ 

Explanation:

• Abbreviations and symbols for engineering drawings are used to express and detail the features of an engineering drawing.
• This contains abbreviations common to the language of individuals who work in the manufacture and inspection of parts and assemblies with engineering drawings.

Explanation:

The leader is never drawn vertical or horizontal or curved. It is drawn at a convenient angle of not less than 30o to the line to which it touches. When pointing to a circle or an arc it is drawn radially.

A leader line is a line referring to a feature (dimension, object, outline etc). It is a continuous thin line.

• If the leader line ends within the outline of an object, it should have a dot at the end.
• It should have an arrowhead if it ends on the outline of an object.
• It should terminate without dot or arrowhead if it ends on a dimension line.​

A circle has an eccentricity of zero, so the eccentricity shows you how "un-circular" the curve is. Bigger eccentricities are less curved.

Different values of eccentricity make different curves:

At eccentricity = 0 we get a circle

for 0 < eccentricity < 1 we get an ellipse

for eccentricity = 1 we get a parabola

for eccentricity > 1 we get a hyperbola

for infinite eccentricity, we get a line

Representation Factor (R. F)

\({\rm{R}}.{\rm{F}} = {\rm{}}\frac{{{\rm{Length\;of\;object\;on\;drawing}}}}{{{\rm{Actual\;length\;of\;the\;object}}}} = \frac{{\cos 45^\circ }}{{\cos 30^\circ }} = \frac{{1/\sqrt 2 }}{{\sqrt 3 /2}} = \sqrt {\frac{2}{3}} \)

Explanation:

Datum plane:

• A theoretical plane or axis is established by real features on an object for the purpose of defining the datum reference frame.
• A datum is a theoretical exact plane, axis or point location that GD&T or dimensional tolerances are referenced to.

Datum reference frame:

• A system of three mutually perpendicular planes is used as the coordinate system for geometric dimensioning.