# Engineering Drawing Basic | Interview Question and Answers – Part 3

Engineering Drawing , graphics , Machine Drawing Interview, viva , oral Examination Question and Answers For Mechanical Engineering Students .

Engineering Drawing Basic –  Part 1 | Part 2 | Part 3 | Part 4

Q51 – What is a sectional view? Why sectional views are used in drawing?

Ans51 – The view obtained after cutting the object in order to show the inner details by an imaginary cutting plane is known as sectional view. Sectional views are used in drawing to show the interior details of the object, which are not visible to the observer from outside.

Q52 – What is a cutting plane or section plane?

Ans52:- The imaginary plane by which the object is assumed to be cut is called the cutting plane or sectional plane. They may be perpendicular or parallel to one of the principle planes and either perpendicular or inclined to the other plane. These planes are represented by their traces.

Q53 – What are section or hatching lines?

Ans53 – The lines used to represent the material which has been cut by the cutting plane are called section lines. They are also called hatchings or crosshatchings. These are equally spaced lines inclined at 45º to the horizontal.

Q54 – What do you mean by sections of solids?

Ans54 – the solids which are cut by the section planes to visualize the internal constructional details of the invisible features are known as section of solids.

Q55 – What is apparent section?

Ans55:- The projection of the section on the plane to which it is inclined is called as apparent section.

Q56 – What is true section?

Ans56:- The projection of the section on a plane parallel to the plane will show the true shape of the section.

Q57 – How will you classify sections of solids? Or
What are the different positions of a section plane w.r.t. two reference lines? Or
What are the types of sections of solids?

Ans57:- 1) Section of solids obtained by horizontal planes.
2) Section of solids obtained by vertical planes.
3) Section of solids obtained by auxiliary inclined planes.
4) Section of solids obtained by auxiliary vertical planes.
5) Section of solids obtained by profile plane.

Q58 – What do you understand by V.T. and H.T. of section plane?

Ans58 –

• Horizontal trace (H.T) – H.T. of a section plane is a line in which the plane meets the H.P.
• Vertical trace (V.T.) – V.T. of a section plane is a line in which the plane meets the V.P.

Q59 – What do you mean by Frustum?

Ans59 – When the section plane is parallel to the base plane of a cone or pyramid, it will form a frustum.

Q60 – What do you mean by truncated?

Ans60 – When the section plane is inclined to the base plane of a solid, it will form a truncated.

Q61 – What do you understand by intersection of surfaces?

Ans61 – The lines or curves which are formed when surfaces of two solids intersect with each other are known as intersection of surfaces or interpenetration of solids.

Q62 – What are the lines or curve of intersection or interpenetration?

Ans62:- When a solid penetrates into another solid, their surfaces meet in a line called the line or curve of intersection or interpenetration.

Q63 – Give the practical applications of the intersection of surfaces or interpenetration of solids.

Ans63:- It is used in (i) sheet metal shop (ii) pipe fittings (iii) boiler fittings (iv) aeroplane construction (e.g. wings, fuse lags etc.) (v) Automobile layout works (e.g. body wheel house, chairs etc.)

Q64 – Name the methods of plotting the lines of intersection or inter-penetration of solids?

Ans64:- 1) Line method or piercing point method
2) Cutting plane method

Q65:- How will you classify the intersecting surfaces?

Ans65:-

1) the intersection of plane surfaces
2) The intersection of two curved surfaces
3) The intersection of a plane surface and a curved surface

Q66 – What do you mean by development of surfaces?

Ans66:- A layout of the complete surface of a three dimensional object on a plane surface is called its development or pattern.

Q67:- What is stretch out or girth line?

Ans67:- The stretch out or girth line is the length of the pattern or development and is given by the perimeter of the object measured in a plane at right angles to the axis. This term is used in patterns of objects having a constant cross section for their full length. e.g. prisms and cylinders.

Q68 – What is the principle of development?

Ans68 – The development is based on the principle which indicates that every line on the development must show the true length of the corresponding line on the surface of the object for which development is required.

Q69 – What are the different methods of development of surfaces?

Ans69:- 1) Parallel line development
3) Triangulation development
4) Approximate method

Q70 – Why the true lengths of slant edges are determined?

Ans70 – The true length of slant edges are determined because every line on the development must show the true length of the corresponding line on the surface of the object to be developed.

Q71 – What are the applications of development of surfaces?

Ans71:- It is used in the fabrication of simple to highly complicated shapes from flat surfaces in sheet metal shops, in the construction of boilers, pattern making, tunnels, buckets, chimney etc.

Q72 – What is a point?

Ans72 – A point is that which has simply position but no magnitude. It is generally represented by a very small circle or dot.

Q73 – What do you mean by octants?

Ans73 – When the three planes i.e. H.P., V.P. and P.P. divide the entire space into eight quadrants, then these quadrants are known as octants.

Q74 – What is the difference between first angle and third angle projection? Which angle projection is recommended by B.I.S. now a days?
Or
What are the types of orthographic projections?

Ans74:-

First angle projection:-In this projection the object is assumed to be situated in first quadrant, i.e. in front of V.P and above HP the projections obtained on these planes is called first angle projection. The symbol for the first angle projection is

Third angle projection: – In this Projection the object is assumed to be situated in the third quadrant that is below HP and behind VP .The front view comes below the XY line and the top view above it. The symbol for the third angle projection is

Now a day we are working with first angle projection because it is recommended by the B.I.S and it is adopted by almost all the countries of the world since 1983.

Q75 – Why the projections of an object is not drawn in second and fourth quadrants?

Ans75 – The projections of an object is not drawn in second and fourth quadrants because the overlapping will take place. It will become very difficult to understand the views.

Engineering Drawing Basic –  Part 1 | Part 2 | Part 3 | Part 4