CBSE Class 12 Question Paper 2025 Solution Engineering Graphics

Marking Scheme
Strictly Confidential
(For Internal and Restricted use only)
Senior School Certificate Examination, 2025
SUBJECT NAME: ENGINEERING GRAPHICS (Q.P. CODE 68)

General Instructions: -
1 You are aware that evaluation is the most important process in the actual and
correct assessment of the candidates. A small mistake in evaluation may lead to
serious problems which may affect the future of the candidates, education
system and teaching profession. To avoid mistakes, it is requested that before
starting evaluation, you must read and understand the spot evaluation
guidelines carefully.
2 “Evaluation policy is a confidential policy as it is related to the
confidentiality of the examinations conducted, Evaluation done and
several other aspects. Its leakage to public in any manner could lead to
derailment of the examination system and affect the life and future of
millions of candidates. Sharing this policy/document to anyone,
publishing in any magazine and printing in Newspaper/Website, etc.
may invite action under various rules of the Board and IPC.”
3 Evaluation is to be done as per instructions provided in the Marking Scheme. It
should not be done according to one’s own interpretation or any other
consideration. Marking Scheme should be strictly adhered to and religiously
followed. However, while evaluating, answers which are based on latest
information or knowledge and/or are innovative, they may be assessed
for their correctness otherwise and due marks be awarded to them. In
class-XII, while evaluating two competency-based questions, please try
to understand given answer and even if reply is not from marking
scheme but correct competency is enumerated by the candidate, due
marks should be awarded.
4 The Marking scheme carries only suggested value points for the answers.
These are in the nature of Guidelines only and do not constitute the complete
answer. The students can have their own expression and if the expression is
correct, the due marks should be awarded accordingly.
5 The Head-Examiner must go through the first five answer books evaluated by
each evaluator on the first day, to ensure that evaluation has been carried out
as per the instructions given in the Marking Scheme. If there is any variation,
the same should be zero after deliberation and discussion. The remaining
answer books meant for evaluation shall be given only after ensuring that there
is no significant variation in the marking of individual evaluators.

68 1 P.T.O.

6 Evaluators will mark (√) wherever answer is correct. For wrong answer CROSS
‘X’ be marked. Evaluators will not put Right (✓) while evaluating which gives
an impression that answer is correct and no marks are awarded. This is most
common mistake which evaluators are committing.
7 If a question has parts, please award marks on the right-hand side for each
part. Marks awarded for different parts of the question should then be totalled
up and written in the left-hand margin and encircled. This may be followed
strictly.
8 If a question does not have any parts, marks must be awarded in the left-hand
margin and encircled. This may also be followed strictly.
9 If a student has attempted an extra question, answer of the question deserving
more marks should be retained and the other answer scored out with a note
“Extra Question”.
10 No marks to be deducted for the cumulative effect of an error. It should be
penalized only once.
11 A full scale of marks 70 has to be used. Please do not hesitate to award full
marks if the answer deserves it.
12 Every examiner has to necessarily do evaluation work for full working hours
i.e., 8 hours every day and evaluate 20 answer books per day in main subjects
and 25 answer books per day in other subjects (Details are given in Spot
Guidelines).This is in view of the reduced syllabus and number of questions in
question paper.
13 Ensure that you do not make the following common types of errors committed
by the Examiner in the past:-
● Leaving answer or part thereof unassessed in an answer book.
● Giving more marks for an answer than assigned to it.
● Wrong totalling of marks awarded on an answer.
● Wrong transfer of marks from the inside pages of the answer book to the
title page.
● Wrong question wise totalling on the title page.
● Wrong totalling of marks of the two columns on the title page.
● Wrong grand total.
● Marks in words and figures not tallying/not same.
● Wrong transfer of marks from the answer book to online award list.
● Answers marked as correct, but marks not awarded. (Ensure that the
right tick mark is correctly and clearly indicated. It should merely be a
line. Same is with the X for incorrect answer.)
● Half or a part of answer marked correct and the rest as wrong, but no
marks awarded.
14 While evaluating the answer books if the answer is found to be totally incorrect,
it should be marked as cross (X) and awarded zero (0)Marks.
15 Any unassessed portion, non-carrying over of marks to the title page, or
totalling error detected by the candidate shall damage the prestige of all the

68 2

personnel engaged in the evaluation work as also of the Board. Hence, in order
to uphold the prestige of all concerned, it is again reiterated that the
instructions be followed meticulously and judiciously.
16 The Examiners should acquaint themselves with the guidelines given in the
“Guidelines for Spot Evaluation” before starting the actual evaluation.
17 Every Examiner shall also ensure that all the answers are evaluated, marks
carried over to the title page, correctly totalled and written in figures and words.

18 The candidates are entitled to obtain photocopy of the Answer Book on request
on payment of the prescribed processing fee. All Examiners/Additional Head
Examiners/Head Examiners are once again reminded that they must ensure
that evaluation is carried out strictly as per value points for each answer as
given in the Marking Scheme.

Specific Instructions:
a) Marks are to be awarded in proportion to the work done.

b) Mistakes in dimensioning up to ± 1.0 mm may be ignored.

c) In dimensioning, arrow-heads of various types, as per
SP: 46-2003 codes are acceptable. However, where space is too
small for an arrowhead, oblique stroke or dot may be employed.

d) In sectioned view of question no. 23 and in question no. 24, if
hidden edges / lines are drawn, no marks should be deducted.

e) Other standard methods of drawing / proportions for isometric
scale, nuts, heads of bolts, screws etc. employed by examinees,
may also be accepted.

f) The answers/solutions must be evaluated adhering to marking
scheme and no marks should be deducted without mistake.

68 3 P.T.O.

Set 4
MARKING SCHEME
ENGINEERING GRAPHICS

SECTION – A

Q. 1 to Q.14 14×1=14

1. (B) Hidden edges

2. (C) The interior details of a complicated object

3. (D) (iv)

4. (A) (i) and (iv) only

5. (C) (iii)

6. (B) (ii)

7. (B) (iii) only

8. (A) 1-(ii), 2-(i), 3-(iv), 4-(iii)

9. (A) Square thread

10. (C) 30 mm

11. (D) (iii) only

12. (C) Shaft

13. (A) Constraints of manufacturing

14. (B) 1-(ii), 2-(iii), 3-(i), 4-(iv)

68 4

SECTION – B

Q. 15 to Q.18 4×1=4

15. (B) isometric projection and orthographic projection

16. (A) Solids of revolution

17. (B) 420 mm

18. (D) 1540 cm2

Q. 19 to Q.22 4×1=4

19. (D) (iv)

20. (A) represent conventionally the external V-thread

21. (C) Headless screw

22. (B) To prevent the relative motion

23. (a) TURN-BUCKLE (ASSEMBLY):

(i) FRONT VIEW, UPPER HALF IN SECTION (13)

 Drawing the upper half of the body (3)
with hatching lines (1) 4
 Drawing the lower half of the body 3
 Drawing both rods inserting 54 mm in the body with arc
(11/2 x 2=3), conventional representation of threads (1x2=2)
and conventional ends of rods (1/2 x2=1) 6
(ii) RIGHT SIDE VIEW (8)

 Four circles including broken circle 4
 Hatching lines showing conventional end of rod B (1/2) and
cutting plane (1/2) 1
 Hidden lines representing the central portion of the body at a
distance of 44 mm 3

68 5 P.T.O.

Details: (6)

 Printing the title 1
 Scale used 1
 Projection Symbol 1
 Six important dimensions 3

OR
23. (b) SLEEVE AND COTTER JOINT (DIS-ASSEMBLY):

(i) SLEEVE

(a) FRONT VIEW LOWER HALF IN SECTION (8)

 Drawing the boundary of sleeve with rounds of R4 (3) and a
horizontal line in lower half showing a hole of Ø 32 (1) 4
 1
Drawing the cotter holes with taper in the lower half (2 /2),
showing correctness of taper in cotter holes (1/2) as given in the
question 3
 Drawing hatching lines in lower half 1

(b) LEFT SIDE VIEW (6)

 Circle of Ø 52 (2) and circle of Ø 32 (11/2) 31/2
 Both cotter holes 2
 Cutting plane 1
/2

(ii) COTTER – B

(a) FRONT VIEW (4)

 Vertical straight edge (1) and taper edge (1) 2
 Upper and lower horizontal lines with curves 2

(b) LEFT SIDE VIEW (3)

 Two parallel vertical edges 1
 Upper and lower ends of cotter 2

Details: (6)

 Printing the titles of both 1

68 6

 Scale used 1
 Projection Symbol 1
 Six important dimensions 3

SECTION – C
24. (a) ISOMETRIC SCALE : (4)

(i) Drawing lines at an angle of 30O and 45O. 1
(ii) Marking of divisions of 10mm, including divisions of first part of one
mm on true length. 1
(iii) Projections from true length 1:1 to get points on isometric length,
construction of isometric scale. 1
(iv) Printing ‘True length / Scale 1:1’, ‘Isometric length/Isometric scale’
and marking angles of 30O and 45O. 1

24. (b) ISOMETRIC PROJECTION OF TRIANGULAR PRISM: (9)

(i) Drawing helping figure 1
1
(ii) Drawing inverted isometric triangles [front (3) and rear (11/2)] 4 /2
(iii) Drawing horizontal three edges 11/2
(iv) Drawing axis perpendicular to V.P. (1/2) and
direction of viewing (1/2) 1
(v) All Dimensions 1

Note: For incorrect position, (1) mark should be deducted.

25. (a) EXTERNAL METRIC THREAD PROFILE: (8)

(i) Horizontal distances (equal to half of pitch), vertical distances
(D=0.866P, D/8 and D/6) marked correctly. 2
(ii) Drawing of crests (1) and roots (1) of threads (minimum two), flanks
(1) drawn correctly. 3
(iii) Drawing hatching lines with conventional break . 1
(iv) Standard dimensions. 2

Note: If sketched freehand, instead of drawing to scale 1:1, two (2)
marks should be deducted, in all..

68 7 P.T.O.

OR
25. (b) FRONT VIEW OF VERTICAL HEXAGONAL BOLT : (8)

(i) Drawing hexagonal head of the bolt resting on HP (Across the Flat or
across the corner). 3
(ii) Drawing of chamfering arcs. 1
1
(iii) Drawing the threaded (1), unthreaded ( /2) portion and conventional
end (1/2) of the shank. 2
(iv) Standard dimensions. 2

Note: 1. For incorrect position, (1) mark should be deducted.

2. If sketched freehand, instead of drawing to scale 1:1, two (2) marks
should be deducted, in all.

68 8

68
23
(a)
Ø32
26 14 64
A' Ø62 54

32

Ø18
A

9
Ø22 LH
Ø22 RH

44 160

RIGHT SIDE VIEW FRONT VIEW, UPPER HALF IN SECTION

ASSEMBLY OF TURN-BUCKLE SCALE - 1:1

P.T.O.

23
(b)

140 Ø32

8 Ø52
R4

A

3

A'
25 25

FRONT VIEW, LOWER HALF IN SECTION LEFT SIDE VIEW

SLEEVE
4

27
40

25
40

TAPER ON
THIS SIDE

8
SCALE - 1:1

FRONT VIEW LEFT SIDE VIEW

COTTER - B

DISASSEMBLY OF SLEEVE AND COTTER JOINT

68 10

m
m
24

70
(a)

60
50
TH
G
40

45°
N
LE
E
30
2 U
TR

70
0

60

30°
50
10

40 H
NGT
30 LE
0

2 0 IC
E TR
10

1 0 M
0 IS O
10
ISOMETRIC SCALE
24
(b)
35
35 60

HELPING FIGURE
30°

ISOMETRIC PROJECTION

68 11 P.T.O.

P 0.5P D=0.866P d=0.61P D/8 D/6
25
(a) 50 25 43.3 30.5 5.4 7.2

P = PITCH 0.5P

D/8

60°
d
D

D/6

EXTERNAL METRIC THREAD

25 Ød OR Ød

(b) Ø0.8d Ø0.8d
d

d
R=

R=
2d+6

2d+6

60°
R=d
0.8 d

0.8 d

30°

1.5d+3

FRONT VIEW (ACROSS FLAT) FRONT VIEW (ACROSS CORNER)

HEXAGONAL HEADED BOLT
d 0.8d 1.5d+3 2d+6
25 20 40.5 56

68 12