Is used to draw curves which are not circular?

Drafting tools may be used for measurement and layout of drawings, or to improve the consistency and speed of creation of standard drawing elements. Tools such as pens and pencils mark the drawing medium. Other tools such as straight edges, assist the operator in drawing straight lines, or assist the operator in drawing complicated shapes repeatedly. Various scales and the protractor are used to measure the lengths of lines and angles, allowing accurate scale drawing to be carried out. The compass is used to draw arcs and circles. A drawing board was used to hold the drawing media in place; later boards included drafting machines that sped the layout of straight lines and angles. Tools such as templates and lettering guides assisted in the drawing of repetitive elements such as circles, ellipses, schematic symbols and text. Other auxiliary tools were used for special drawing purposes or for functions related to the preparation and revision of drawings. The tools used for manual technical drawing have been displaced by the advent of computer-aided drawing, drafting and design (CADD).

The ancient Egyptians are known to have used wooden corner rulers. Ancient Nuragic people in Sardinia used compasses made of bronze, like the one displayed in showcase 25 in the Nuragic department of the National Archeological Museum G. A. Sanna in Sassari. In ancient Greece, evidence has been found of the use of styli and metal chisels, scale rulers and triangle rulers. Excavations in Pompeii have found a bronze tool kit used by the Romans, which contained triangle rulers, compasses and a ruler to use with a pen.

Although a variety of styli were developed in ancient times and were still being used in the 18th century, quills were generally used as the main drawing tool. Styli were also used in the form of ivory or ebony pencils.

Protractors have been used to measure and draw angles and arcs of a circle accurately since about the 13th century, although mathematics and science demanded more detailed drawing instruments. The adjustable corner ruler was developed in the 17th century, but a feasible screw-tightened version not until the 1920s.

In the 17th century, a stylus that could draw a line with a specific width called a ruling pen was developed. The stylus had two curved metal pieces which were joined by a screw. Ink was trickled between the blades, from which it flowed evenly across the paper. The basic model was maintained for a long time, with minor modifications, until the 1930s when the German technical drawing pens came to the market.

Artists (including Leonardo da Vinci and Albrecht Dürer, Nicholas Bion and George Adams) generally made drawing tools for themselves. Industrial production of technical drawing instruments started in 1853, when Englishman William Stanley (1829–1909) founded a technical manufacturing company in London. Even then, however, most tools were still made by hand.

In the 1930s the equipment available expanded: drawing apparatus and Rapidograph-drawing pens appeared, improving the line quality and, especially, producing consistent line width. In addition to the Rapidograph stylus, a more traditional Grafos-type stylus was used for a long time, where different line widths were achieved by changing the pen nib. For instance in Finland Grafos was commonly used as a primary drawing tool still in the early 1970s.

Equipment changed radically during the 1990s, when computer-aided design almost completely ousted drawing by hand. Technical design has changed from drawing by hand to producing computer-aided design drawings, where drawings are no longer "drawn", but are built from a virtually-produced model. Drawings are not necessarily produced in hard copy at all, and if they are needed they are printed automatically by a computer program. Hand-drawn designs however are still widely used in the draft design stage.

Traditional and typical styli used for technical drawing are pencils and technical pens.

Pencils in use are usually mechanical pencils with a standard lead thickness. The usual line widths are 0.35 mm, 0.5 mm, 0.7 mm and 1.0 mm. Hardness varies usually from HB to 2H. Softer lead gives a better contrast, but harder lead gives a more accurate line. Bad contrast of the lead line in general is problematic when photocopying, but new scanning copy techniques have improved the final result. Paper or plastic surfaces require their own lead types.

In most cases, the final drawings are drawn with ink, on either plastic or tracing paper. The pen is generally a Rapidograph-type technical pen, a marker pen that draws lines of consistent width (so-called steel marker pen). The pen has an ink container which contains a metal tube, inside which is a thin metal needle or wire, the soul. Ink is absorbed between the needle and the tube wall, preventing an excessive amount of ink from being released. The needle has a weight and by waving the pen back and forth the needle is released and the ink can run. Originally, the tank was filled from an ink bottle; newer pens use ink cartridges.

Each line width has its own stylus. The line width is standardized: In Finland, the most commonly used set is 0.13 mm, 0.18 mm, 0.25 mm, 0.35 mm, 0.50 mm and 0.70 mm. Separate styli are used for tracing paper and plastic, because plastic requires a harder pen tip. To function well they require regular maintenance, the finest marker pens in particular.

The drawing board is an essential tool. Paper will be attached and kept straight and still, so that the drawing can be done with accuracy. Generally, different kind of assistance rulers are used in drawing. The drawing board is usually mounted to a floor pedestal in which the board turns to a different position, and also its height can be adjustable. Smaller drawing boards are produced for table-top use. In the 18th and 19th centuries, drawing paper was dampened and then its edges glued to the drawing board. After drying the paper would be flat and smooth. The completed drawing was then cut free.: 1-2  Paper could also be secured to the drawing board with drawing pins or even C-clamps. More recent practice is to use self-adhesive drafting tape to secure paper to the board, including the sophisticated use of individualized adhesive dots from a dispensing roll. Some drawing boards are magnetized, allowing paper to be held down by long steel strips. Boards used for overlay drafting or animation may include registration pins or peg bars to ensure alignment of multiple layers of drawing media.

A T-square is a straightedge which uses the edge of the drawing board as a support. It is used with the drafting board to draw horizontal lines and to align other drawing instruments. Wooden, metal, or plastic triangles with 30° and 60° angles or with two 45° angles are used to speed drawing of lines at these commonly used angles. A continuously adjustable 0–90° protractor is also in use. An alternative to the T-square is the parallel bar which is permanently attached to the drawing board. It has a set of cables and pulleys to allow it to be positioned anywhere on the drawing surface while still remaining parallel to the bottom of the board. The drafting machine replaces the T-square and triangles.

A drafting machine is a device which is mounted to the drawing board. It has rulers whose angles can be precisely adjusted with a controlling mechanism. There are two main types of apparatus: an arm-type parallelogram apparatus based on a hinged arm; and a track-type apparatus which moves on a rail mounted to the top of the drawing board. The accuracy of the arm type apparatus is better in the middle of the board, decreasing towards the edges, whereas a track machine has a constant accuracy over the whole board. The drawing head of a track-type drafting machine slides on bearings in a vertical rail, which in turn is moved along a horizontal, top-mounted rail. Both apparatus types have an adjustable drawing-head with rules attached to a protractor scale so that the angle of the rules may be adjusted.: 35–36

A drafting machine allows easy drawing of parallel lines over the paper. The adjustable angle between the rulers allows the lines to be drawn in varying accurate angles. Rulers may also be used as a support for separate special rulers and letter templates. The rules are replaceable and they can be for example scale-rules.

Drawing apparatus has evolved from a drawing board mounted parallel ruler and a pantograph, which is a device used for copying objects in an adjustable ratio of sizes.

French curves are made of wood, plastic or celluloid. Some set squares also have these curves cut in the middle. French curves are used for drawing curves which cannot be drawn with compasses. A faint freehand curve is first drawn through the known points; the longest possible curve that coincides exactly with the freehand curve is then found out from the French curves. Finally, a neat continuous curve is drawn with the aid of the French curves.: 12–13

Rulers used in technical drawing are usually made of polystyrene. It is used for drawing lines and connecting points. Rulers come in two types according to the design of their edge. A ruler with a straight edge can be used with lead pencils and felt pens, whereas when a technical pen is used the edge must be grooved to prevent the spread of the ink.

A scale ruler is a scaled, three-edged ruler which has six different scales marked to its sides. A typical combination for building details is 1:20, 1:50, 1:100, 1:25, 1:75 and 1:125. There are separate rulers for zoning work as well as for inch units. Today scale rulers are made of plastic, formerly they were made of hardwood. A pocket-sized version is also available, with scales printed on flexible plastic strips.

Compasses are used for drawing circles or arc segments of circles. One form has two straight legs joined by a hinge; one leg has a sharp pivot point and the other has a holder for a technical pen or pencil. Another form, the beam compass, has the pivot point and pen holder joined by a trammel bar, useful when drawing very large radius arcs. Often a circle template is used instead of a compass when predefined circle sizes are required.

Templates contain pre-dimensioned holes in the right scale to accurately draw a symbol or sign.

Letter templates are used for drawing text, including digits and letter characters. Diagrams are usually of a standard letter shape and size to conform to standards of encodings (e.g. DIN or ANSI). For example, in Finland the series used is 1.8 mm, 2.5 mm, 3.5 mm, 5.0 mm and 7.0 mm. Except for the very biggest ones, the templates are only suitable for technical pen drawing.

For drawing circles and circle-arcs, circle templates which contain a set of suitably-sized holes are used. Templates are also available for other geometric shapes such as squares and for drawing ellipses, as well as many specialized varieties for other purposes.

There are also specific templates to provide user with the most common symbols in use in different branches of designing. For example, the architect templates can be used to draw different sized doors with their "opening arcs", building and equipment symbols and furniture. The templates also provide the symbols for thermal insulation.

Two methods of drawing smooth curves in manual drafting are the use of French curves and flat splines (flexible curves). A French curve is a drawing aid with many different smoothly-varying radiused curves on it; the manual drafter can fit the French curve to some known reference points and draw a smooth curved line between them. A spline is a flexible ruler, usually rubber or plastic coated with a metal "backbone", which can be smoothly shaped to follow a desired curve and allows drawing a smooth line between initial reference points. Sometimes a spline is temporarily held in position with small weights.

A perspective machine is an instrument designed to create perspective drawings.

Silk-paper-like translucent drafting paper that wrinkles when wetted. It is primarily suitable for pencils and felt tip pens. Pencil marks can be corrected to some extent with an eraser.

Sandwich-paper-like, thin translucent sheet of paper. Manufactured in different strengths, the surface may be slightly polished. This paper also wrinkles upon wetting. Suitable for pencil and felt tipped pens, and with limitations for technical pens. An eraser can be used for pencil lines. Ink is difficult to erase without damage.

Drafting linen was formerly used for technical drawings. It was durable and held up to handling, but it was difficult to use in modern whiteprints for reproduction, and shrinking was a concern.

Polished sandwich paper-like, translucent thick paper, which comes in different strengths. Wrinkles upon wetting. Suitable for both graphite pencils and technical pens. An eraser or sharp scraper tool is used for corrections.

Translucent plastic film, which is usually of gray or a light khaki shade. Common types are 0.05, 0.07 and 0.10 mm thick. These films are also used in photocopying. The most commonly used materials are polyesters, and sometimes also PVC or polycarbonate; arguably, a proprietary eponym or genericized trademark for this is called Mylar.

Drawing inks can be divided into two groups: India ink and polymer inks. India ink is used on paper and drafting film plastics. The most commonly used India ink is a colloidal mixture of water and carbon black.

Dry transfer decals can speed the production of repetitive drawing elements such as borders, title blocks, line types, shading, and symbols. They were frequently used in the production of schematic drawings, maps, and printed circuit board artwork, for example. Dry transfer lettering such as Letraset was used especially in lettering larger size document annotations, or when consistency of lettering was especially required.

Many copies of technical drawings may be required in the construction of a project. Reproductions must be accurate as to size and shape, but for many purposes need not be permanent. The blueprint process was first used for mechanical reproduction of drawings. Drawing offices may use diazo or whiteprint processes. Where the volume of drawings reproduced justifies the cost of the machine, a large format photocopier using xerography can reproduce drawings at lower cost than re-plotting them.

The following are the commonly used Drawing Instruments in a drawing office.

Drawing board is one of the main equipment of Draughtsman. It is used for supporting the drawing paper/tracing paper for making drawings. It is made of well seasoned wood strips of about 25 mm thick or Masonite, free from knots and warping. It should be softer enough to allow insertion and removal of drawing pins. Two battens are fastened to the board by screws, in slotted joints. They prevent warping and at the same time permit expansion and contraction of the strips due to the change of moisture in the atmosphere.

Standard drawing boards are designated as follows as per IS:1444-1989.

One of the shorter edges of the drawing board, is provided with an “ebony edge” (hard wood) fitted perfectly straight. The working edge (ebony) must be straight.

Now-a-days the drawing boards are available with laminated surfaces. The flatness can be checked by placing a straight edge on its surface. If no light passes between them, the surface is perfectly flat.

It is one of the drawing instruments which is of ‘T’ shape, made of well seasoned wood. It has two parts., head and blade. One of the edge of the blade is the working edge. The blade is screwed to this head such that the working edge is at right angle to head.

The standard ‘T’ square are designated as follows with dimensions shown in mm; as per IS:1360-1989.

The ‘T’ squares is used with its head against the ebony edge of the drawing board to draw horizontal lines, parallel lines and to guide/hold the setsquares, stencils etc.

‘T’ square should never be used as a hammer or as guide for trimming papers.

It serves the functions of a Tee square, set square, protractor and scale. They come in different sizes and a pattern called ‘Pantograph’ type. It is fitted on the top left side, edge of the drafting board, mounted on an adjustable frame or table. It requires large area of working place. The angle of the drafting board can be adjusted by pedal operating system. There are two counter weights to balance the angular position of the board and the drafting head. It is more suitable for production drawing office.

On the other end, a protractor head H with swiveling and locking arrangement is fitted with two scales at right angles.

The protractor head has a spring loaded clutch relieving handle, which rotates and locks at 150 intervals automatically. For setting any angle other than multiples of 150, the clutch spring is released and by rotating the centre knob, the zero line is set to the required angle and the friction clutch knob is tightened. It is capable of rotating 180º, thereby any angle can be set.

The scales are beveled on both sides, graduates to 1:1 & 1:2., They can be reversed with the help of dovetail slide fitting.

There is a fine adjusting mechanism on the drafting head to set the scale parallel to the edge of the board. The scales also can be adjusted if there is any error in measuring 900 between them.

Mini drafter is an important device used for making drawing quickly& accurately. This instrument gives faster drawing as it like the purpose of T Square, Set Square, Protractor and scales.

When, on a drawing, if a part of a line or some lines among many other lines need to be erased or modified, in 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.

Transparent celluloid /Plastic setsquares are preferred and are commonly used rather ebonite ones. They are two in number, each having one corner with 90°. The setsquare with 60°-30° of 250 mm long and 45° of 200mm long is convenient for use. Setsquares sometimes loose their accuracy due to internal strains. So they should be tested periodically.

Sometimes set squares have french curves. Set squares are used to draw all straight lines except horizontal lines. It is convenient to draw horizontal lines using Mini drafter.

With the help of Mini drafter and manipulating the 45°, 30°- 60° setsquares, angular lines in the multiples of 15°; Parallel lines to a given inclined line and perpendicular to can be drawn.

Set squares with graduated, bevel edge and French curve openings are preferable. They are also used to draw smooth curves. Setsquare should never be used as guide for trimming papers.

Scales are used to transfer and or to measure the dimensions. They are made of wood, steel, ivory, celluloid or plastic, stainless steel scales are more durable. Different types of scales used. They are either flat, bevel edged or triangular cross-section. Scales of 15 cm long, 2 cm wide or 30 cm long 3.5 cm wide flat scales are in general use. Thin section or bevel edged scales are preferred over thick flat scales. Parallax error will be nil or least while using thin / tapered edge scales.

Protractor is an instrument for measuring angles. It is semi-circular or circular in shapes and is made of flat celluloid sheet. The angles can be set or measured from both sides, aligning the reference line and point ‘0’ with the corner point of the angle. Protractor can also be used to divide a circle or drawing sectors.

These are made in many different shapes, normally come in sets of 6,12,16 etc. French curves are best suited to draw smooth curves/ arcs (which cannot be drawn by a compass) with ease. To draw a smooth curve using french curve first set it by trial against a part of the line to be drawn, then shift it to the next portions.





Drafting is a task that demands skilled work. The drafter must be careful and patient and must have the right tools to work with and a well-lighted working area. Such facilities help the drafter to produce accurate and neat work.

A standard set of drawing equipment should include the following items:

Drawing board, drawing paper, and thumbtacks

T-square

30°, 45°, and 60° plastic triangles

Engineers’, architects’, or mechanical drafters’ triangular ruler

Metal and plastic protractor

Adjustable triangle

French curve

Set of drawing instruments

Ink technical pens

Drawing pencils with leads of varying hardness

Or a drafter may use a computer with special software

The drafter works on a table that can be tilted to any desired position. Pencil drawings are made on tracing vellum paper, held on the inclined surface of the drawing board by drafting dots or tape. Transparent paper, called tracing paper, is then placed over the completed pencil drawing. Following the pencil outlines, the drafter neatly traces the drawing in ink on the tracing paper or film.

The drawing board is of soft wood, usually about 30 to 42 inches (76 to 107 centimeters) wide. It provides a smooth surface for drawing. The left edge of the board must be perfectly straight because it guides the T-square. Drawing paper should have a surface that will take pencil and drawing ink and that can be erased easily.

2. Which of the following instrument is made of thin strips of wood arranged in a line to form a rectangle and on which, the drawing is made? a) Mini – drafter b) Drawing Board c) Protractor d) Scale Answer: b Explanation: The drawing board is made up of thin sheets of seasoned softwood, arranged in a line so as to form a rectangle. Then it is fitted with two battens on the respective parallel sides of the board. The battens are attached with the help of screws.

3. Which of the following tools is used to draw horizontal lines? a) Mini – drafter b) Protractor c) T – square d) French curve Answer: c Explanation: T – squares are made up of hard wood, plastics, etc. It consists of two parts; stock and blade. The stock slides on the drawing board and the horizontal lines are drawn from the working edge on the side of the blade. The angle between the stock and the blade is 90˚.

4. Which of the following instrument can be used to draw accurate perpendicular lines, parallel lines and angular lines? a) Mini – drafter b) T – square c) Protractor d) Set square Answer: a Explanation: Mini – drafters are used to draw perpendicular lines, parallel lines and angular lines. They consist of blades, protractor head, double bar link mechanism, screw and clamp. The blades have markings corresponding to the engineering scale.

5. According to the Indian Standard Institute (ISI), which among the following designation has the size 1000 x 700 (in mm)? a) B0 b) B1 c) B2 d) B3 Answer: b Explanation: The designation B1 is 1000 x 700 mm in size whereas B0, B2 and B3 designations are 1500 x 1000 mm, 700 x 500 mm and 500 x 300mm respectively. These designations denote the dimensions of the drawing boards. Standard dimensions are used to simplify the production process.

6. Which is the most common tool used for drawing circles? a) French curve b) Mini – drafter c) Divider d) Compass Answer: d Explanation: Compass is used to draw circles. Its design is similar to the divider, except in compass there is a provision for the attachment of pencil or lead in one of the legs of the compass. The divider is used to measure and repeat the dimensions when they are repeated.

7. For drawing circles with a large radius, which of the following tool is used? a) Bow compass b) Lengthening bar compass c) Divider d) Protractors Answer: b Explanation: In a lengthening bar compass, there is a provision for increasing the radius of the circle greater than the total open length of the compass. This helps in drawing very large circles with the help of medium sized compasses.

8. Which of the following drawing tools is used by architects for making blueprints? a) Drawing Pencils b) Dusters c) Ink Pen d) Erasers Answer: c Explanation: Ink Pen is used to draw the blueprints by architects and draftsmen. They are used to draw lines onto the tracing paper. They are used for making the final drafts of the drawing made in pencil. Drawing pencils have generally leads which drawn on paper can be erased. This does not happen with the ink pen.

9. Which of the following drawing tool is not used to set the drawing sheet onto the drawing board? a) Drawing clips b) Drawing pins c) Divider d) Adhesive Tape Answer: c Explanation: Divider is a drawing tool used to replicate the dimensions when the dimensions are repeated. Drawing clips, drawing pins and adhesive tapes are used to attach the drawing sheet onto the drawing board. These attachments are temporary attachments and can be removed after the drawing is completed.

10. According to the Indian Standard Institution (ISI), what is the size of the designation A3 in mm? a) 420 x 297 b) 841 x 594 c) 1189 x 841 d) 297 x 210 Answer: a Explanation: The size of the designation A3 in mm is 420 x 297. The designations A0, A1, A2, A4 and A5 have sizes 1189 x 841 mm, 841 x 594 mm, 594 x 420 mm, 297 x 210 mm and 210 x 148 mm respectively. Standardizing helps in uniformity of the products all over the nation and will avoid local variations.

11. Which of the following drawing tool is used to transfer dimensions when there is a repetition of the dimensions? a) Compass b) Protractor c) Divider d) Mini – Drafter Answer: c Explanation: Divider is used to transfer dimensions when there is a repetition of the dimensions. It is the faster method than using a scale and then marking the dimension again. Protractors are only used to mark angles and the compass is used to draw circles.

12. Which of the following grades of leads is the hardest? a) 6B b) 5H c) 4B d) 6H Answer: d Explanation: 6H is the hardest grade of lead. The softest grade is 6B. HB is the medium soft grade. Generally, for educational purposes, 2HB pencils are used to make drawings. B is soft and H is medium hard. As the prefix number increases, the softness increases in B and the hardness increases in case of H.

13. For marking angles, which of the following drawing tool is used? a) Protractor b) Divider c) Compass d) French curve Answer: a Explanation: Protractors are used to mark angles from 0˚ to 180˚. There are markings on the semicircular area of the protractor. The least count of protractor for educational purpose is 1˚. The accuracy of marking angles is highest in protractor.

14. Using 30˚ – 60˚ – 90˚ and 45˚ – 45˚ – 90˚ set squares, which of the following angle is not possible to draw? a) 45˚ b) 30˚ c) 10˚ d) 90˚ Answer: c Explanation: Using the proper combination of both the set squares, one can draw multiple angles with a 30˚ angle minimum. If T-square and mini-drafter also used, the minimum accurate angle that we can draw is 15˚. Set squares are generally used to draw vertical and inclined lines.

15. Which is the instrument used to draw parallel lines fast? a) Set square b) Ruler scale c) Protractor d) Roll-n-draw Answer: d Explanation: Using roll-n-draw scales, we can draw parallel lines very accurately and fast. They are used to draw parallel lines in the horizontal direction, vertical direction and also in inclined planes. The general dimension of the roll-n-draw scale is 30 cm and 15 cm. The scale is rolled on the paper to achieve parallel lines.

16. How many battens will be there for a Drawing board? a) 1 b) 2 c) 3 d) 4 Answer: b Explanation: Generally drawing board has dimensions of 1000 x 1500, 700 x 1000, 500 x 700, 350 mm x 500 mm, and made of well-seasoned soft wood, so there would be no bending while life increases. And also if a size of drawing board increases widely then the board will be fabricated with another 1 or 2 battens.

17. The part that doesn’t belong to T-square is __________ a) Working edge b) Blade c) Stock d) Ebony Answer: d Explanation: Working edge and Stock are parts of T- square those which make 90 degrees with each other, the blade is the long bar that exists in T-Square. Ebony is part of Drawing board in which T-square is fitted to draw lines.

18. The angle which we can’t make using a single Set-square is ________ a) 45o b) 60o c) 30o d) 75o Answer: d Explanation: 45o can be drawn using 45o Set-square, and 30o, 60o can be drawn using 30o – 60o Set-square, but to draw 75o degrees we need both Set-squares. That is only if we keep 30o of set-square adjacent with 45o set-square we can get 75o. And also multiple angles can be achieved using protractor.

19. The angle which we can’t make using both the Set-squares is _____________ a) 15o b) 105o c) 165o d) 125o Answer: d Explanation: 15o can be made by keeping 45o and 30o adjacent to each other on the line perpendicular to the line for which 15ois made. Likewise for 105o and 165o also if we just change the alignment with the required line it possible. But to make 125o there is no such combination available for Set-squares.

20. Small bow compass can draw circles less than _____ mm radius. a) 25mm b) 30mm c) 35mm d) 40mm Answer: a Explanation: A normal Small bow compass is capable of drawing circles less than the 25mm radius. This is because of the arrangement of a screw in between the legs of the compass. But any other normal compass can’t give us perfect circles whose radius is less than 25mm.

21. Which is not the use of divider? a) To divide curved or straight lines into the desired number of equal parts b) To draw circles c) To transfer dimensions from one part of the drawing to another part d) To set-off given distances from the scale to the drawing Answer: b Explanation: Divider can be used for those purposes as mentioned in options. But we cannot use divider as a compass and even if we want the compass to be used as divider we can change the pencil part with needle attachment.

22. The cardboard scales are available in a set of _______ scales. a) six b) ten c) eight d) twelve Answer: c Explanation: The cardboard scales are available in a set of eight scales. They are designated from M1 to M8 which has scale of 1:1, 1:2.5, 1:10, 1:20, 1:50, 1:200, 1:300, 1:400, and 1:1000. These are standard scales used.

23. _________ is used to draw curves which are not circular. a) Compass b) Protractor c) French curves d) Pro circle Answer: c Explanation: French curves are used for drawing curves which can’t be drawn with a compass. A faint freehand curve is first drawn through the known points. Longest possible curves exactly coinciding with the freehand curve are then found out from the French curve. Finally, a neat continues curve is drawn with the aid of the French curve.

24. The areas of the two subsequent sizes of drawing sheet are in the ratio ____ a) 1:5 b) 1:4 c) 1:2 d) 1:10 Answer: c Explanation: A successive format size (from A0 to A5) is obtained by halving along the length or doubling along the width. So the areas of the two subsequent sizes are in the ratio 1:2. Likewise in reverse order (from A5 to A0), the ratio will be 2:1.

25. The sizes from A0 to A5 increases. a) True b) False Answer: b Explanation: The sizes from A0 to A5 decreases, A5 (148 mm x 210 mm), A4 (210 mm x 297 mm), A3 (297 mm x 420 mm), etc. A successive format size is obtained by doubling along the width or halving along the length.

26. The increase in hardness is shown by the value of the figure put in front of the letter H, 2H, 3H, and 4H etc. a) True b) False Answer: a Explanation: Letters HB denote the medium grade where the increase in hardness is shown by the value of the figure put in front of the letter H, viz. 2H, 3H, and 4H etc. Similarly, the grade becomes softer according to letter B, 2B, 3B and 4B etc.

27. What is the next size of 210 mm x 297 mm in drawing papers? a) 148 mm x 210 mm b) 297 mm x 420 mm c) 420 mm x 594 mm d) 105 mm x 148 mm Answer: b Explanation: 210 mm x 297 mm is A4 size, next one is A3 (297 mm x 420 mm), which came doubling along the width. And the next size is obtained by doubling the width i.e. A2 (420 mm x 594mm) and so on.

28. The Grade becomes ______ according to the figure placed in front of the letter B, 2B, 3B, 4B etc. a) harder b) lighter c) darker d) softer Answer: d Explanation: The increase in hardness is shown by the value of the figure put in front of the letter H, 2H, 3H, and 4H etc. Similarly, the grade becomes softer according to the figure placed in front of the letter B, 2B, 3B, and 4B etc.

29. Parabolic curves is not used in ________ a) Arches b) Bridges c) Sound reflectors d) Boring

30. By an equation how can you define a cycloid? a) y = a(1-sin α) b) x = a(α – cos α) c) x = a(α – sin α) d) x = a(1- sin α)

31. When the point is within the circle, the curve is called an ________ a) Inferior trochoid b) Superior trochoid c) Inscribed trochoid d) Superior trochiod Answer: a Explanation: Trochoid is a curve generated by a point fixed to a circle, within or outside its circumference, as the circle rolls along a straight line. The curve generated below shows us the inferior trochoid.

32. Figure below represents a section (shaded) obtained due to intersection by a plane that is parallel to the axes of the cones, what it the section called? a) Parabola b) Hyperbola c) Ellipse d) Cycloid Answer: b Explanation: Hyperbola concept originated in Greek, can be defined as a set of points in a plane whose distances to two fixed points in the plane have a constant difference. It is formed by the intersection of a plane with a right circular cone. Equation of parabola: x2/a2 – y2/b2 = ±1.

33. For eccentricity in ellipse (e) which relation is correct? a) e < 1 b) e = 1 c) e > 1 d) e = ∞ Answer: a Explanation: Eccentricity can be defined as a parameter associated with every conic section. It can be thought of a measure of how much the conic section deviates from being circular. When (e < 1 Ellipse), (e = 1 Parabola), (e > 1 Hyperbola), (e = ∞ straight line), (e = 0 Circle).

34. When a uniform and flexible chain hangs from two pegs, its weight is uniformly distributed along its length. The shape it takes is called a _________ a) Catenary b) Parabola c) Hyperbola d) Ellipse Answer: a Explanation: When a uniform and flexible chain hangs from two pegs, its weight is uniformly distributed along its length. The shape it takes is called a catenary. The catenary curve has a U-like shape, superficially similar in appearance to a parabola, but it is not a parabola. The catenary is also called the alysoid, chainette, or, particularly in the materials sciences, funicular. This figure blow represents a catenary and a parabola.

35. A curve defined by an equation x2/a2 + y2/b2 = 1 is known as ________ a) Ellipse b) Directrix c) Parabola d) Hyperbola Answer: a Explanation: A plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane that cuts the axis and the surface of the cone.

8. _________ is used to draw curves which are not circular. Explanation: French curves are used for drawing curves which can't be drawn with a compass.