JNTU
JNTU B.Tech I ENGINEERING GRAPHICS Previous Question Paper (January - 2021 - R18)
Answer any three questions. All questions carry equal marks.
Main
Draw a vernier scale of R.F. = 5 to read 1/5 cm and 1/25 cm and to measure up to 5 cm. Mark on the scale distances of 2.12 cm and 4.29 cm.
Answer
To construct the vernier scale, first calculate the length of the scale: Length = R.F. × Maximum length = 5 × 5 cm = 25 cm. Draw a line 25 cm long and divide it into 5 equal parts, each representing 1 cm. Subdivide the first division into 10 parts, each representing 0.1 cm. For the vernier scale, take 11 divisions of the primary scale (1.1 cm) and divide them into 10 equal parts. Each vernier division equals 0.11 cm, and the least count is 0.11 - 0.10 = 0.01 cm (or 1/100 cm). To mark 2.12 cm, place the vernier index at 2.1 cm and move 2 vernier divisions to the right. To mark 4.29 cm, place the vernier index at 4.2 cm and move 9 vernier divisions to the right.
The major axis of an ellipse is 150 mm long and the minor axis is 100 mm long. Find the foci and draw the ellipse. Draw a tangent to the ellipse at a point on it 25 mm above the major axis.
Answer
To construct the ellipse, draw the major axis AB (150 mm) and minor axis CD (100 mm) intersecting at O. To find the foci, take radius equal to half the major axis (75 mm) and center at C; draw arcs intersecting AB at F1 and F2. Use the concentric circle method: draw two circles with diameters 150 mm and 100 mm. Divide both circles into 12 equal angular parts. Project points vertically from the outer circle and horizontally from the inner circle to find points on the ellipse curve. Connect these points with a smooth curve. To draw the tangent at a point P (25 mm above the major axis), first identify point P on the ellipse. Join P to F1 and F2. Draw the bisector of the angle F1PF2; this bisector is the normal to the ellipse at P. Draw a line perpendicular to the normal passing through P to obtain the required tangent.
A hexagonal plate of side 20 mm rests in the HP on one of its sides inclined at 45° to the VP. The surface of the plate makes an angle of 30° with the HP. Draw the front and top views of the plate.
Answer
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The point A of a line AB is in HP and 60 mm in front of VP. The point B is in VP and 40 mm above HP. The distance between projectors is 70 mm. Draw the projections of the line and find the true length and inclinations.
Answer
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A pentagonal pyramid, having side of base 30 mm and axis 90 mm long, is resting on its base with one of its base edges parallel, nearer, and 15 mm away from VP. It is cut by a plane perpendicular to HP, inclined at 40° to VP, and 10 mm away from the axis. Draw the sectional top view and front view. Also draw the true shape of the section.
Answer
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A lamp shade is formed by cutting a cone of base 144 mm diameter and 174 mm height by a horizontal plane at a distance of 72 mm from the apex and by another plane inclined at 30° to HP and passing through one extremity of the base. Draw the development of the lamp shade.
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A cube of 30 mm side rests centrally on the top of a cylindrical slab of 50 mm diameter base and 40 mm height lying on the ground. The axis of both solids are in the same straight line, and the base sides of the cube are equally inclined to the V.P. Draw the isometric projection of the solid.
Answer
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