# Engineering Drawing Basic | Interview Question and Answers – Part 4

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

Q76 – When the auxiliary planes are used?

Ans76 – The auxiliary planes are used in order to view the true shape of an inclined surface. The projection drawn on the auxiliary plane is known as the auxiliary view and gives the true shape of the inclined surface.

Q77 – What are the types of auxiliary planes?

Ans77:-The plane placed at any angles to the principle planes is called auxiliary plane. Auxiliary planes are of two types.
1) Auxiliary vertical plane (A.V.P.):-It is perpendicular to the HP and inclined to the VP. Projection on an AVP is called auxiliary front view.
2) Auxiliary inclined plane (A.I.P.):-It is perpendicular to the VP and inclined to the HP. Projection on AIP is called auxiliary top view.

Q78 – Define a straight line.

Ans78 – A straight line is defined as the shortest distance between the two points.

Q79:- What is true length of a line?

Ans79:-When a straight line is inclined to one plane and parallel to the other, its projections on the plane to which it is parallel will show its true length.

Q80 – What do you mean by projections of a straight line?

Ans80:-To draw the front view, top view and side view of a straight line is called projection of a straight line.

Q81:- What is inclination of a straight line?

Ans81:-It is defined as the angle which the line makes with the plane. As such a line has two inclinations i.e.

inclination with the HP is represented by an angle θº and inclination of a line with VP is represented by an angle Фº.

Q82 – What are the apparent angles of inclinations?

Ans82 – The angle made by the front view of a line with reference line (x-y line) is called apparent angle of inclination α. The angle made by the top view of a line with reference line (x-y line) is called apparent angle of inclination β.

Q83 – Name the methods to determine the true length and true inclinations of a straight line.

Ans83:-The following methods are used when the line is inclined to both the reference planes.
1) Rotation method
2) Auxiliary plane method
3) Trapezoid method.

Q84 – What are skew lines?

Ans84:-Any two lines that are not parallel with each other and do not intersect are called skew lines.

Q85 – What is the trace of a straight line?

Ans85:-When a straight line is inclined to a plane, it will meet that plane, produced if necessary. The point in which the line or line produced meets the plane is called its trace.
1) Horizontal trace:-The point of intersection of the line with the HP is called the horizontal trace.
2) Vertical trace:-The point of intersection of the line with the VP is called the vertical trace.

Q86 – Define a plane.

Ans86:-A flat surface generated by moving a straight line in space is called a plane. A plane fig. has only two dimensions i.e. length and breadth.

Q87 – What is the difference between a plane and a lamina?

Ans87:-

Plane:-A plane has no boundary and it extends to infinity in all directions.
Lamina:-The plane which has limited extent is also known as lamina.

Q88 – What are the types of planes?

Ans88:-There are two types of planes.
1) Perpendicular planes:-The planes which are perpendicular to one or both the reference i.e. VP and HP are called perpendicular planes.
2) Oblique planes:-The planes which are inclined to both the reference planes i.e. VP and HP are called oblique planes.

Q89 – What is the trace of a plane?

Ans89:-The lines in which the planes meet the reference planes i.e. HP and VP are called the traces of the planes. There are two types of traces of planes.
1) Horizontal trace:-The intersection of a plane with the horizontal plane is called the horizontal trace.
2) Vertical trace:-The intersection of a plane with the vertical plane is called the vertical trace.

Q90 – What is a solid?

Ans90 – An object having three dimensions i.e. length, breadth and height is called a solid. E.g. Prisms, Pyramids, cone, cylinder etc.

Q91 – What are different types of solids?

Ans91:- Solids may be divided into two main groups.
1) Polyhedra or polyhedron: – A polyhedra is defined as a solid bounded by planes called faces. Which meet in straight lines called edges?
2) Solids of revolution: – The solids which are formed by the revolution of plane figures are known as solids of revolution. e.g. Cylinders, cones, sphere etc.

Q92:- What are right solids?

Ans92:- A solid is said to be a right solid if its axis is perpendicular to its base or its end faces.

Q93 – What are oblique solids?

Ans93:- If the axis of a solid is inclined at an angle other than 90º to its base or end faces, it is called as an oblique solid.

Q94:- What are regular solids?

Ans94:- If all the edges of the base or the end faces of a solid are equal in length and form regular plane figures, it is said to be a regular solid.

Q95 – What is the difference between prism and pyramid?

Ans95:-

1) Prism:– A prism is a polygon having two equal and similar end faces, called bases, parallel to each other and joined by other side faces which are rectangles or parallelograms.
2) Pyramid: – A pyramid is a polyhedron, having a polygon as its base and a number of triangular faces, equal to the number of sides of the base polygon, meeting at a common point called the apex or vertex.

Q96 – What are the various positions which a solid can take w.r.t. the reference planes?

Ans96 – The following are the different positions which a solid can take w.r.t. the reference planes.
(i) The solid resting on base on H.P., with its axis perpendicular to H.P., and parallel to V.P.
(ii) The solid resting on face on H.P., with its axis perpendicular to V.P., and parallel to H.P.
(iii) The solids resting on face on H.P., with its axis parallel to H.P. and V.P.
(iv) The solid with its axis inclined to one plane and parallel to the other.
(v) The solid with its axis inclined to both the reference planes i.e., H.P. and V.P.

Q97:- What is an isometric view?

Ans97:- If the projection of an object is so drawn that all the three axis of the object are equally inclined to the plane of projection then it is called an isometric view.

Q98:- What is an isometric scale?

Ans98:- The proportion by which the actual length is converted to isometric length is called as isometric scale.

Q99 – What are isometric axis?

Ans99 – The three lines OA, OB and OC meeting at a point and making 120º angles with each other are termed as isometric axis.

Q100:- What are isometric and non isometric lines?

Ans100:- The lines which are parallel to isometric axis are called as isometric lines. The lines which are not parallel to isometric axis are called non isometric lines.

Q101 – What are iso-metric planes?

Ans101 – The planes representing the faces of an isometric view of the cube as well as the other planes parallel to these planes are called isometric planes.