Karnataka SSLC Question Paper 2025 Answer Key Elements of Mechanical Engineering

Government of Karnataka
Karnataka Secondary Education Examination Board

Question Paper
ANSWER KEY

A
CCE RF/RR
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KARNATAKA SCHOOL EXAMINATION AND ASSESSMENT BOARD,
MALLESHWARAM, BENGALURU – 560 003

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Subject : ELEMENTS OF MECHANICAL ENGINEERING - IV
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Date : 01. 04. 2025 ] [ Max. Marks : 80

Qn.
Value Points Total
1. Rectilinear motion is converted into rotary motion
with the help of
(A) valves and piston
(B) crank and connecting rod
(C) connecting rod and piston
(D) crank and piston
(B) crank and connecting rod 1
2. Four stroke sequence of operation is
(A) suction, exhaust, compression and power
(B) suction, power, exhaust and compression
(C) suction, compression, power and exhaust
(D) suction, compression, exhaust & power
(C) suction, compression, power and exhaust 1

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Qn.
Value Points Total
3. A diesel engine has
(A) one valve (B) four valves
(C) three valves (D) two valves
(D) two valves
1
4. Mother of all machine tools is
(A) Milling machine (B) Lathe
(C) Grinding machine (D) Drilling machine
(B) Lathe
1
5. Process of enlarging the hole size is known as
(A) Spot facing (B) Drilling
(C) Reaming (D) Boring
(D) Boring
1
6. A plane has
(A) three dimensions (B) four dimensions
(C) two dimensions (D) one dimension
(C) two dimensions
1
7. If a circular plane is inclined at 30º with the H.P. and
60º with the V.P., its side view will be
(A) Ellipse (B) Straight line
(C) Circle (D) True shape
(B) Straight line
1
8. If the top view of a plane is a rhombus, the object may
be
(A) Square (B) Parallelogram
(C) Octagon (D) Rectangle
(A) Square
1

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Qn.
Value Points Total
9. A solid has

(A) one dimension (B) three dimensions

(C) two dimensions (D) four dimensions

(B) three dimensions
1
10. The projectors in isometric views are

(A) converging
(B) diverging

(C) parallel to plane of projection

(D) perpendicular to plane of projection

(D) perpendicular to plane of projection
1
11. a) Write the types of I.C. engines on the basis of method
of cooling.

Following are the two types :
i) Air cooled engines
ii) Water cooled engines
2
b) Explain any three parts of I.C. engine.

i) Cylinder : The heart of the engine is the cylinder
in which fuel is burnt and power is developed

ii) Piston : The piston is a close fitting hollow-
cylindrical plough moving to and fro in the
cylinder.

iii) Connecting rod : It is a link that connects the
piston and the crank-shaft by means of pin
joints. It converts the rectilinear motion of the
piston into rotary motion of the crank shaft.
3

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Qn.
Value Points Total
c) Write the comparison between four-stroke and two-
stroke I.C. engines.
Sl.
Principle Four-stroke Two-stroke
No.
i) Number of Requires four Requires only
strokes strokes of the two strokes of
per cycle piston of the piston to
complete one complete one
cycle of cycle of
operation operation
ii) Power Power Power is
developed in developed in
every every revolution
alternative of the crank
revolution of shaft
the crank shaft
iii) Fly wheel Heavy fly wheel Lighter fly wheel
is required is required
iv) Valves Inlet and outlet The piston itself
valves are opens and closes
opened and
closed by
mechanical
valves
v) Engine More effective Very high
cooling effective
vi) Lubrica- Less More
tion oil
consumpt-
ion
vii) Noise Less More 5
12. a) Explain E.C. engines and I.C. engines.
E.C. engines : Means external combustion engines.
Fuel combustion takes place outside the engine
cylinder.
I.C. engines : Means internal combustion engines.
Fuel combustion takes place inside the engine
cylinder. 2

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Qn.
Value Points Total
b) Classify the different types of lathe.
i) Speed lathe
ii) Bench lathe
iii) Tool room lathe
iv) Engine lathe
v) Capstan and turret lathe
vi) Automatic lathe 3
c) Explain with a neat diagram a four-stroke diesel I.C.
engine.
Following are the four-strokes :
i) Suction stroke
ii) Compression stroke
iii) Power stroke
iv) Exhaust stroke
i) Suction stroke

During this stroke piston is moving from
T.D.C. to B.D.C.
Inlet valve is opened and outlet valve is
closed
Through inlet valve only pure air is coming
into the cylinder

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Value Points Total
ii) Compression stroke

During this stroke piston is moving from
B.D.C. to T.D.C.
Both the valves are closed
Pure air inside the engine cylinder is get
compressed
Compression ratio 16 : 1 to 20 : 1
At the end of the stroke, overcompressed
hot air diesel is injected from the fuel
injector.
iii) Power stroke (Working stroke) :

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During this stroke piston is moving from
T.D.C. to B.D.C.
Both the valves are closed
The high pressure burnt gases forces the
piston to perform this stroke
Hence the power is released.
iv) Exhaust stroke

During this stroke piston is moving from
B.D.C. to T.D.C.

Inlet valve is closed and outlet valve is
opened

Through outlet valve exhaust gas or smoke
is expelled out as on piston moves towards
T.D.C. 5

13. a) List the different types of operation carried out on
lathe.
i) Turning
ii) Thread cutting
iii) Facing
iv) Knurling 2

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Qn.
Value Points Total
b) Explain turning operation on lathe.

Turning operation :
It is the process of removal of excess metal from the
work piece to form a cylindrical surface. The various
types of turning are
i) Straight turning
ii) Rough turning
iii) Smooth or finishing turning
iv) Shoulder turning 3
c) Mention the different types of drilling machines.
Following are the different types of drilling machine :
i) Portable drilling machine
ii) Sensitive drilling machine
iii) Upright drilling machine
iv) Radial drilling machine
v) Gang drilling machine
vi) Multiple spindle drilling machine
vii) Automatic drilling machine
viii) Deep hole drilling machine. 5
14. a)
Draw a neat sketch of lathe and label the parts.

5

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Qn.
Value Points Total
b) A pentagonal lamina of edges 30 mm is resting on
H.P. with one of its corners touching it such that the
plane surface makes an angle of 60º with H.P. Draw
its top and front views.

5
15. a) A circular lamina of 60 mm diameter rests on H.P.
such that the surface of the lamina is inclined at 30º
to H.P. Draw its top and front views.

5

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Qn.
Value Points Total
b) Draw the top and front views of a hexagonal pyramid
of 30 mm side of base and height 70 mm resting with
its base on H.P. such that one of the base edges is
parallel to V.P. and nearer to it.

5
16. Draw the top and front views of a cone of 60 mm
diameter of base and axis 80 mm long lying on H.P.
with its axis inclined at 45º to it and parallel to V.P.

10

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Qn.
Value Points Total
17. The pictorial view of an object is shown in Figure

No. 1. Draw the following orthographic views and

mark the dimensions :

i) Front view — Looking in the direction of arrow 'X'

ii) Top view — Looking in the direction of arrow 'Z'

iii) Side view — Looking in the direction of arrow 'Y'.

Figure No. 1

10

OR

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Qn.
Value Points Total
Draw the isometric view of an object from the given
orthographic views in Figure No. 2.

Figure No. 2

Isometric view 10

CCE RF/RR(A)/101/1830 (MA)

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