TN 12th Question Paper 2025 Basic Electrical Engineering

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8377
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Part III — Vocational Subjects
Ai¨£øh ªß ö£õÔ°¯À & P¸zv¯À
BASIC ELECTRICAL ENGINEERING - THEORY
( uªÌ ©ØÖ® B[Q» ÁÈ / Tamil & English Version )

Põ» AÍÄ : 3.00 ©o ÷|µ® ] [ ö©õzu ©v¨ö£sPÒ : 90
Time Allowed : 3.00 Hours ] [ Maximum Marks : 90

AÔÄøµPÒ : (1) AøÚzx ÂÚõUPЮ \›¯õP £vÁõQ EÒÍuõ GߣuøÚ \›£õºzxU
öPõÒÍÄ®. Aa_¨£v¨¤À SøÓ°¸¨¤ß AøÓU PsPõo¨£õÍ›h®
EhÚi¯õPz öu›ÂUPÄ®.
(2) }»® AÀ»x P¸¨¦ ø©°øÚ ©mk÷© GÊxÁuØS®
AiU÷PõikÁuØS® £¯ß£kzu ÷Ásk®. £h[PÒ ÁøµÁuØS
ö£ß]À £¯ß£kzuÄ®.
Instructions : (1) Check the question paper for fairness of printing. If there is any lack of fairness,
inform the Hall Supervisor immediately.
(2) Use Blue or Black ink to write and underline and pencil to draw diagrams.

£Sv & I / PART - I

SÔ¨¦ : (i) AøÚzx ÂÚõUPÐUS® Âøh¯ÎUPÄ®. 15x1=15

(ii) öPõkUP¨£mkÒÍ |õßS ©õØÖ ÂøhPÎÀ ªPÄ® Hئøh¯
Âøhø¯z ÷uº¢öukzxU SÔ±mkhß Âøh°øÚ²® ÷\ºzx GÊuÄ®.
Note : (i) Answer all the questions.
(ii) Choose the most appropriate answer from the given four alternatives and write
the option code and the corresponding answer.

[ v¸¨¦P / Turn over

8377 2

1. ÷©Û-ø» ªß-öuõ-hº £Qº-©õ-Úz-vÀ ©µU-P®-£® G¢u ªß-Ú-Êz-uz-vØS HØ-Óx ?
(A) 11 Q.÷Áõ. (B) 22 Q.÷Áõ. (C) 66 Q.÷Áõ. (D) 440 Q.÷Áõ.
Wooden poles for supporting transmission lines are used for Voltages upto __________.
(a) 11 kV (b) 22 kV (c) 66 kV (d) 440 kV

2. ö£¸®-£õ-¾® ªß- £-Qº-©õ-Úz-vØS £¯ß-£-kz-u¨-£-k® Phz-v __________.
(A) Á¾¨-£-kz-u¨-£mh GL-S-hß Ti-¯ A¾-ª-Û-¯U Phz-v
(B) uõ-ª-µ®
(C) A¾-ª-Û-¯®
(D) GL-S
Generally which conductor is used for power transmission ?
(a) Aluminium Conductor with Steel Reinforced
(b) Copper
(c) Aluminium
(d) Steel

3. xz-u-|õ-P® Gß-£-x __________ Euõ-µ-n®.
(A) E÷»õ-P-©À-»õ ¤Ó ö£õ-¸-ÐU-S
(B) C¸®-£À-»õ E÷»õ-Pz-vØ-S
(C) P»¨¦ GLS E÷»õ-Pz-vØ-S
(D) C¸®¦ P»¢u E÷»õ-Pz-vØ-S
Zinc is an example of __________.
(a) Non-metal
(b) Non-ferrous metal
(c) Alloy
(d) Ferrous metal

4. RÌ- P s- h - Á Ø- Ö Ò JÎ- ° - ¯ À ö£õ- ¸ m- P - Î À BØ- Ó À ©õØ- Ô - P Íõ- P ¨ £¯ß- £ - k - Á x
Gx ?
(A) ÷»\º (B) JÎ CøÇU P®-¤
(C) `›-¯z-u-P-k (D) GÀ.C.-i
Which one of the following is used as energy convertor in optical materials ?
(a) LASER (b) Optic fibre cable
(c) Solar Panel (d) LED

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5. ÷|ºzvø\ ªß-ÚõU-Q-°À EØ-£z-v-¯õ-S® ©õÖ ªß-Ú-Êz-uzøu ÷|º ªß-Ú-Êz-u-©õP
©õØ-Ó¨ £¯ß-£-k-Áx :
(A) Põ-•-÷hm-hº (B) Põº-£ß öuõ-k-Â
(C) •øÚ ÁøÍ-¯® (D) ]¼¨-›[
In DC generator, the alternating emf is converted into direct by means of __________.
(a) Commutator (b) Carbon brush
(c) End rings (d) Slip-ring

6. ö£õ-x-ÁõP TÇõU-Q-°À £¯ß-£-kz-u¨-£-k® ªß-÷Úõi Gx ?
(A) ªß-÷uUQ xÁU-P ªß-÷Úõ-i (B) ¤›¢u {ø» ªß-÷Úõ-i
(C) ²Û-Áº-\À ªß-÷Úõ-i (D) ÷åhm x¸-Á ªß-÷Úõ-i
Generally which motor is used in electric mixie ?
(a) Capacitor start motor (b) Split phase motor
(c) Universal motor (d) Shaded pole motor

7. ªß-ÚP EÒÍ-Pzøu Põ¨-¤-k-Áx :
(A) ö\®¦ CǨ-ø£U SøÓUP
(B) îì-h-›-]ì CǨ-ø£U SøÓUP
(C) C¯¢-v-µ-Â-¯À CǨ-ø£U SøÓUP
(D) Gi ªß-\õ-µ® CǨ-ø£U SøÓU-P
Armature core is laminated :
(a) to reduce copper loss
(b) to reduce hysteresis loss
(c) to reduce mechanical loss
(d) to reduce eddy current loss

8. ö©ß-ø©-¯õÚ xÁU-Q-°À ªß-Ú-Êz-uz-øuU SøÓUP Gx £¯ß-£-k-Q-Óx ?
(A) øu›ì-hº (B) KÁº ÷»õk ›÷»
(C) öuõk •øÚ-PÒ (D) ÷|õ ÷ÁõÀm ›½ì _¸Ò
Which component is used for voltage reducing in soft starter ?
(a) Thyrister (b) Over load relay
(c) Contact pointers (d) No volt release coil

[ v¸¨¦P / Turn over

8377 4

9. xÁU-Pz-vß-÷£õx, AøÚzx ªß-÷Úõ-i-P-Ю Gkz-xU-öPõ-Ò-Ю ªß-÷Úõm-hz-vß
©v¨¦ :
(A) E¯º-Ä (B) §ä-¯® (C) ªP AvP (D) SøÓ-Áõ-P
While starting, value of current taken by all the motors is :
(a) high (b) zero (c) very high (d) less

10. uÛ¨-£mh C¯U-Q __________ £¯ß-£-kz-u¨-£-k-Q-Óx.
(A) ªß £Ð yU-Q-P-ÎÀ (B) Po-Û-P-ÎÀ
(C) öám £®-¦-P-ÎÀ (D) öÁØ-Ô-hz y´-ø©-¯õU-Q-P-ÎÀ
The individual drive is used in __________.
(a) Cranes (b) Computers
(c) Jet pumps (d) Vacuum cleaners

11. ªß-\õµ Â{-÷¯õP •øÓUS __________ •UQ-¯-©õÚ £S-v BS®.
(A) ªß-_ØÖ¨- £»-øP (B) _Âm-_
(C) vÓß ªß-_ØÖ (D) Pm-k¨-£õmk _Âm-_
For electrical power distribution system __________ is an important part.
(a) Panel board (b) Switch
(c) Power circuit (d) Control switch

12. ]Ó¢u ªß-P-hz-vUS ÷uøÁ-¯õÚ Ai¨-£øh Sn® __________.
(A) SøÓ¢u ªß-u-øh (B) AvP C¯¢-vµ Á¼ø©
(C) AvP ªß-Põ¨¦ Á¼-ø© (D) ]Ó¢u £ØÓøÁ¨-¦z -ußø©
The basic property needed for a good conductor is :
(a) Low resistance (b) High mechanical strength
(c) High di-electric strength (d) Best soldering property

13. •Ê _¸-Î-øhz yµ EÀ-ø»-°À J¸ _¸-Îß C¸ £U-P[-P-ÐU-Q-øh÷¯ EÒÍ
ªß-Û-¯À ÷Põ-n® :
(A) 1808 (B) 608 (C) 3608 (D) 1208
In full pitched winding, the electrical angle between two coils is :
(a) 1808 (b) 608 (c) 3608 (d) 1208

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14. ªß-ÚÀ uõ[-Q-PÒ __________ US Cøh-÷¯ ªß {ø» öÁÎ-÷¯Ø-Ó¨ £õ-øuø¯
ÁÇ[P £¯ß-£-k-Q-Óx.
(A) ªß-÷ÚØ-Ó® ö\´-¯¨-£mh ÷©P[-PÒ ©Ø-Ö® {» Cøn¨¦
(B) ªß-÷ÚØ-Ó® ö\´-¯¨-£mh ÷©P[-PÒ ©Ø-Ö® L÷£ì
(C) ªß-÷ÚØ-Ó® ö\´-¯¨-£mh ÷©P[-PÒ ©Ø-Ö® ªß \¨-øÍ
(D) ªß-÷ÚØ-Ó® ö\´-¯¨-£mh ÷©P[-PÒ ©Ø-Ö® {³m-µÀ
Lightning arrester is used to provide a path to the static electric discharge between
__________.
(a) charged clouds and earth
(b) charged clouds and phase
(c) charged clouds and supply
(d) charged clouds and neutral

15. ö£õ-x-ÁõP Gz-uøÚ ÁøP {» Cøn¨-¦-PÒ £¯ß-£-kz-u¨-£-k-Q-Óx ?
(A) Cµs-k (B) |õß-S (C) I¢-x (D) ‰ß-Ö
How many types of earthing are commonly used ?
(a) Two (b) Four (c) Five (d) Three

£Sv & II / PART - II
SÔ¨¦ : GøÁ÷¯Ý® £z- x Â-ÚõU-P-ÐUS Âøh¯-ÎU-P-Ä®. ÂÚõ Gs 28 &US
Pmhõ¯©õP Âøh-¯-ÎUP-Ä®. 10x3=30
Note : Answer any ten questions. Question number 28 is Compulsory.
16. £õ-x-Põ¨¦ Põ¨-¤-hÀ ö\´-Á-uß |ß-ø©-PÒ ¯õøÁ ?
What are the uses of guarding ?

17. ö£õ-Ô-°-¯À ö£õ-¸m-P-Îß ÁøP-P-øͨ £m-i-¯-¼-kP.
List out the broad classification of the engineering materials.

18. «m-]z-ußø© (Elasticity) & Áøµ-¯-Ö.
Define Elasticity.

19. Põ-•-÷hm-hº & ]Ö-S-Ô¨¦ GÊ-x-P.
Write short notes on Commutator.

20. "÷ÁP ÁÊU-PÀ' & Áøµ-¯Ö.
What is meant by ‘slip-speed’ ?

21. ys- h À ªß- ÷ Úõ- i - ° À £¯ß- £ - k z- u ¨- £ - k ® £À- ÷ ÁÖ ÁøP- ¯ õÚ xÁU- Q - P Ò
¯õøÁ ?
What are the different types of starters used in an induction motor ?

[ v¸¨¦P / Turn over

8377 6

22. ö©ß-ø©-¯õÚ xÁU-Q-°ß ªß Áøµ-£-hzøu Áøµ-¯-Ä®.
Draw the block diagram of Soft Starter.

23. £» ªß-÷Úõi C¯UQ Gß-ÓõÀ GßÚ ?
What is called multi motor drive ?

24. ÷|ºz-vø\ ªß C¯UQ & Áøµ-¯-ÖU-P-Ä®.
Define DC Electric drive.

25. {µ-»õUP \õ-u-Ú® £ØÔ GÊ-xP.
Write about programming device.

26. ªß-Ú-Êzu EÖ-v¨-£-kz-x-uÀ Gß-ÓõÀ GßÚ ?
What is meant by Voltage Stabilization ?

27. ©i¨¦ ÁøP EÀø» Gß-ÓõÀ GßÚ ?
What is lap-winding ?

28. Â{-÷¯õP Aø©¨-¤À ªß Áõ´a-\m-h® & SÔ¨¦ ÁøµP.
Write short notes on Bus Way in distribution system.

£Sv & III / PART - III
SÔ¨¦ : GøÁ÷¯Ý® I¢-x Â-ÚõU-P-ÐUS ©m-k® Âøh¯-ÎU-P-Ä®. ÂÚõ Gs
35 &US Pmhõ¯® Âøh-¯-ÎUP-Ä®. 5x5=25
Note : Answer any five questions. Question number 35 is Compulsory.

29. §mk ÁøP ªß-Põ¨-£õ-Ûß £h® Áøµ¢x £õ-P[-PøÍ SÔ.
Draw the diagram of shackle insulator and label their parts.

30. Phz-x® ö£õ-¸Ò-P-Îß ÁøP-P-øÍ ÂÁ-›.
Explain the types of conducting materials.

31. ÷|ºz-vø\ ªß-÷Úõ-i-°ß £¯ß-PøÍ ÂÁ›.
List out the applications of DC motor.

32. ‰ßÖ •øÚ xÁU-Q-°ß Áøµ-£-hzøu Áøµ¢x Auß £õ-P[-PøÍ SÔ.
Draw the diagram of 3 Point Starter and label its parts.

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33. SÊ ªß-Û-¯UQ £ØÔ GÊv uk¨¦ Áøµ-£-h® Áøµ-P.
Write about Group drive with block diagram.

34. Pm- k ¨- £ õm- k ¨ £»- ø P- ø ¯ J¯- › [ ö\´- ² ®- ÷ £õx PnU- Q À Gkz- x U- ö PõÒÍ
÷Ás-i¯ ö£õ-xÁõÚ SÔ¨-¦-PÒ ¯õøÁ ?
What are the general points that should be taken into account when wiring the Control
Panel ?

35. ¤›¢u {ø» (Split phase) ys-hÀ ªß-÷Úõ-i-°ß £h® ÁøµP.
Draw the diagram of Split phase induction motor.

£Sv & IV / PART - IV
SÔ¨¦ : A- ø Úz- x ÂÚõU- P - Ð U- S ® Âøh¯- Î U- P - Ä ®. ÷uøÁ- ¯ õÚ Ch[- P - Î À
£h® Áøµ-¯Ä®. 2x10=20
Note : Answer all the questions. Draw diagrams wherever necessary.

36. (A) ÷©Ûø» ªß- ö uõ- h - ¸ U- S ®, {»z- u i ªß- Á - h z- v Ø- S ® Cøh- ÷ ¯ EÒÍ
÷ÁÖ-£õ-k-PøÍ Am-h-Á-øn¨-£-kz-xP.
AÀ»x
(B) ÷|ºz-vø\ ªß-ÚõU-Q-°ß ÁøP-P-øͨ £hz-x-hß ÂÁ-›.
(a) Tabulate the differences between the overhead transmission lines and underground
cables.
OR
(b) Explain the different types of DC generators with neat diagram.

37. (A) 4 x¸- Á ®, 24 £ÒÍ[- P Ò öPõsh ‰ßÖ {ø» ©õ- Ö - v ø\ ys- h À
ªß-÷Úõi°À Kµ-kUS ©i¨¦ ÁøP EÀø» _Ø-Ö-Á-uØ-PõÚ PnU-Rk ö\´x
EÀø» Am-h-Á-øn-ø¯z u¯õº ö\´P.
AÀ»x
(B) {» Cøn¨-¤À ¤ß-£Ø-Ó¨-£-k® £õ-x-Põ¨¦ ÁÈ-•-øÓ-PøÍ ö£õ-¸z-u-©õÚ
Áøµ-£-h[-P-Ð-hß _¸U-P-©õP ÂÍUS.
(a) Develop the winding table for a Single Layer Lap winding of 4 poles, 24 slots, AC three
phase induction motor.
OR
(b) Explain briefly the safety measures followed in earthing with suitable diagram.

-o0o-

[ v¸¨¦P / Turn over

Study Materials
Notes

Model Papers Class 6 Notes

Sample Papers Class 7 Notes
Half Yearly Sample Papers Class 8 Notes

Class 9 Notes
Important Resources
Class 10 Notes
Periodic Table
Class 11 Notes
Writing Skills / Formats

Maps of India / World Class 12 Notes

Books and Solutions

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HC Verma Chapter Wise Solutions
RD Sharma Solutions
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