TN 12th Question Paper 2022 Physics

No. of Printed Pages : 11
5917
£vÄ Gs
A Register Number

!5917Physics!
PART - III
C¯Ø¤¯À / PHYSICS

( uªÌ ©ØÖ® B[Q» ÁÈ / Tamil & English Version )

Põ» AÍÄ : 3.00 ©o ÷|µ® ] [ ö©õzu ©v¨ö£sPÒ : 70

Time Allowed : 3.00 Hours ] [ Maximum Marks : 70

AÔÄøµPÒ : (1) AøÚzx ÂÚõUPЮ \›¯õP¨ £vÁõQ EÒÍuõ GߣuøÚa
\›£õºzxU öPõÒÍÄ®. Aa_¨£vÂÀ 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 ©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

5917 2

1. RÌU-Ps-h-ÁØ-ÖÒ C¯Ø-øP-¯õÚ |õ-÷Úõ ö£õ-¸Ò Gx ?

(A) ©nÀ xPÒ (B) ©°-¼-Ó-S

(C) vª[-P-»z-vß ÷uõÀ (D) ©°À A»-S
Which one of the following is the natural nanomaterial ?

(a) Grain of sand (b) Peacock feather

(c) Skin of the whale (d) Peacock beak

2. G»Um- µ õß ~s- ÷ nõU- Q °À £¯ß- £ - k ® G»Um- µ õß- P Ò 14 kV ªß- Ú - Ê zu
÷ÁÖ£õm-iÚõÀ •kU-P¨-£-k-Qß-ÓÚ. C¢u ªß-Ú-Êzu ÷ÁÖ-£õ-k 224 kV BP
Av-P-›U-S®÷£õx, G»Um-µõ-Ûß i&¨-µõ´ Aø» }Í-©õ-Úx :

(A) 4 ©h[S SøÓ-²® (B) 2 ©h[S Av-P-›U-S®

(C) 4 ©h[S Av-P-›U-S® (D) 2 ©h[S SøÓ-²®
In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If
the voltage is changed to 224 kV, then the de-Broglie wavelength associated with
the electrons would :

(a) decrease by 4 times (b) increase by 2 times

(c) increase by 4 times (d) decrease by 2 times

3. £s- ÷ £Ø- Ö ® ø\øP- ° ß Pn- ÷ |- µ Ãa- ] ØS HØ£ Fºv Aø»- ° ß Avº- ö Ás
©õØ-Ó¨-£-k-Áx __________ GÚ¨-£-k®.

(A) Pm-h¨ £s-÷£Ø-Ó® (B) Ãa-_¨ £s-÷£Ø-Ó®

(C) xi¨¦ AP» £s-÷£Ø-Ó® (D) Avº-öÁs £s-÷£-Ø-Ó®
The variation of frequency of carrier wave with respect to the instantaneous
amplitude of the modulating signal is called :

(a) Phase modulation (b) Amplitude modulation

(c) Pulse width modulation (d) Frequency modulation

A

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4. Q Põ-µo Gß-£x __________.

ωr L 1 L
(A) (B)
R R C

XL
(C) (D) CøÁ AøÚz-x®
R

Q factor is equal to __________.

ωr L 1 L
(a) (b)
R R C

XL
(c) (d) All the above
R

5. 1 ö\.«. ©Ø- Ö ® 3 ö\.«. Bµ- • ÒÍ C¸ E÷»õ- P U ÷PõÍ[- P - Ð US •øÓ- ÷ ¯
−1×10 −2 C ©Ø- Ö ® 5×10 −2 C AÍÄ ªß- Þ m- h [- P Ò öPõsh ªß- x - P Ò- P Ò
AÎU- P ¨- £ - k - Q ß- Ó Ú. CÆ-  ¸ ÷PõÍ[- P - Ð ® J¸ ªß Phzx P®- ¤ - ° - Ú õÀ
CønU-P¨-£m-hõÀ ö£›-¯- ÷PõÍz-vÀ, CÖ-v-¯õP C¸U-S® ªß-Þmh ©v¨¦ :
(A) 1×10−2 C (B) 3×10−2 C (C) 2×10−2 C (D) 4×10−2 C
Two metallic spheres of radii 1 cm and 3 cm are given charges of −1×10−2 C and
5×10−2 C respectively. If these are connected by a conducting wire, the final
charge on the bigger sphere is :

(a) 1×10−2 C (b) 3×10−2 C (c) 2×10−2 C (d) 4×10−2 C

6. ¤ß-Á-¸-Á-Ú-ÁØ-ÖÒ Gx ªß- Põ¢u Aø»-¯õ-S® ?

(A) β -Pvº-PÒ (B) γ -Pvº-PÒ
(C) α -Pvº-PÒ (D) CøÁ AøÚz-x®
Which of the following is an electromagnetic wave ?

(a) β-rays (b) γ-rays

(c) α-rays (d) All of the above

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7. JÎ-Â-»-PÀ Gs 1.5 öPõsh Ps-nõ-i¨ £m-h-P® Jß-Ô-ÝÒ PõØ-ÖU SªÌ JßÖ
EÒÍx. (ö\[-Szx £k-P-vº {ø»US A¸-QÀ) J¸ £U-Pz-v-¼-¸¢x £õºU-S® ÷£õx
PõØ-ÖU SªÌ 5 ö\.«. B-Çz-v-¾® ©Ø-öÓõ¸ £U-P® ÁÈ-¯õP £õºU-S® ÷£õx
3 ö\.«. BÇz-v-¾® EÒÍx GÛÀ, Ps-nõ-i¨ £m-h-Pz-vß ui-©ß GßÚ ?

(A) 12 ö\.«. (B) 8 ö\.«. (C) 16 ö\.«. (D) 10 ö\.«.
An air bubble in glass slab of refractive index 1.5 (near normal incidence) is 5 cm
deep when viewed from one surface and 3 cm deep when viewed from the opposite
face. The thickness of the slab is :
(a) 12 cm (b) 8 cm (c) 16 cm (d) 10 cm

8. C¢-v-¯õ-ÂÀ Ãk-P-Îß £¯ß-£õm-iØS 220 V ªß-Ú-Êzu ÷ÁÖ-£õm-iÀ ªß-\õ-µ®
A- Î U- P ¨- £ - k - Q - Ó x. Cx Aö©- › U- P õ- Â À 110 V AÍÄ GÚ AÎU- P ¨- £ - k - Q - Ó x.
C¢- v ¯õÂÀ £¯ß- £ - k z- u ¨- £ - k ® 60 W ªß ÂÍU- Q ß ªß- u - ø h R GÛÀ,
Aö©-›U-Põ-ÂÀ £¯ß-£-kz-u¨-£-k® 60 W ªß ÂÍU--Qß ªß uøh :
(A) R/4 (B) R (C) R/2 (D) 2R
In India electricity is supplied for domestic use at 220 V. It is supplied at 110 V in
USA. If the resistance of a 60 W bulb for use in India is R, the resistance of a
60 W bulb for use in USA will be :
(a) R/4 (b) R (c) R/2 (d) 2R

9. l }Í-•ÒÍ P®¤ Jß-Ôß ÁÈ-÷¯ Y vø\-°À I ªß-÷Úõm-h® £õ´-QÓ
- x. CU-P®-¤ø
- ¯
→
B =
β
3
( i + j + k ) T GßÓ Põ¢-u-¦-»z-vÀ øÁU-S® ÷£õx AU-P®-¤-°ß «x
∧ ∧ ∧

ö\¯À-£-k® »õ-µßì Âø\-°ß Gs-©-v¨¦ :

2 1 1
(A) 2 βIl (B) βIl (C) βIl (D) βIl
3 2 3

A wire of length l carrying a current I along the Y direction is kept in a magnetic

field given by B =
→ β
3
( i + j + k ) T . The magnitude of Lorentz force acting on
∧ ∧ ∧

the wire is :

2 1 1
(a) 2 βIl (b) βIl (c) βIl (d) βIl
3 2 3

A

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10. öÁ¨£ BØ-Óø» Em-P-ÁºÁuõÀ G»Um-µõß-PÒ Eª-Ǩ-£-k-Á-x __________ EªÌÄ
GÚ¨-£-k®.

(A) öÁ¨£ A¯-Û (B) JÎ-ªß

(C) Cµs-hõ® {ø» (D) ¦»

Emission of electrons by the absorption of heat energy is called __________ emission.

(a) Thermionic (b) Photo electric

(c) Secondary (d) Field

11. J¸ P®-¤-°À 45 Â-Úõ-iUS 7.5 A ªß-÷Úõm-h-©õ-Úx £µõ-©-›U-P¨-£-k-Q-Óx. C¢u
÷|µz-vÀ P®-¤-°À EÒÍ ªß-Þm-hz-vß ©v¨¦ :

(A) 6 C (B) 365.5 C

(C) 3 C (D) 337.5 C

If a current of 7.5 A is maintained in a wire for 45 seconds then the charge
flowing through the wire is :

(a) 6C (b) 365.5 C

(c) 3C (d) 337.5 C

12. ÷P-÷uõk Pvº-P-Îß ªß-Þm-h® :

(A) |k-{-ø» (B) ÷|º-S-Ô

(C) Áøµ-¯-ÖU-P¨-£-h-ÂÀ-ø» (D) Gvº-S-Ô

The charge of cathode ray is :

(a) neutral (b) positive

(c) not defined (d) negative

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5917 6

13. J¸ CÓUS ªß-©õØÔ ªß-‰-»z-vß ªß-Ú-Êzu ÷ÁÖ-£õmøh 220 V CÀ C¸¢x
11 V BPU SøÓU-Q-Óx ©Ø-Ö® ªß-÷Úõm-hzøu 6 A CÀ C¸¢x 100 A BP E¯ºz-
x-Q-Óx. Auß £¯-ÝÖ vÓß :
(A) 0.12 (B) 1.2 (C) 0.9 (D) 0.83
A step-down transformer reduces the supply voltage from 220 V to 11 V and
increases the current from 6 A to 100 A. Then its efficiency is :

(a) 0.12 (b) 1.2 (c) 0.9 (d) 0.83

 r 
14. J¸ G»Um-µõ-Ûß ªß-Ú-Êz-u® V=V0 ln  r  GÚU öPõ-kU-P¨-£m-kÒÍx. C[-S
 0
r 0 J¸ ©õ- Ô ¼. ªß- Ú - Ê z- u z- v ØS ÷£õº Aq ©õ- v - › - ø ¯¨ £¯ß- £ - k z- v - Ú õÀ,
•ußø© SÁõs-h® Gs n&I¨ ö£õ-Öz-x n&Áx _Ø-Ö-£õ-øu rn&Cß ©õ-Ö-£õm-iß
ußø© :

1 1
(A) rn ∝ 2 (B) rn ∝ (C) rn ∝ n2 (D) rn ∝ n
n n

 r 
The electric potential of an electron is given by V=V 0 ln  r  , where r 0 is a
 0
constant. If Bohr atom model is valid, then variation of radius of nth orbit rn with
the principal quantum number n is :

1 1
(a) rn ∝ (b) rn ∝ (c) rn ∝ n2 (d) rn ∝ n
2 n
n

15. JÎ-°ß SÖU-Pø» £s-¤øÚ öÁΨ-£-kz-x® {PÌ-Ä :
(A) JÎa-]-u-ÓÀ (B) SÖU-Rmk ÂøÍ-Ä
(C) uÍ ÂøÍ-Ä (D) Â-ή¦ ÂøÍ-Ä
Transverse nature of light is shown in :

(a) scattering (b) interference

(c) polarisation (d) diffraction

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£S-v - II / PART - II

SÔ¨¦ : GøÁ÷¯Ý® BÖ ÂÚõUPÐUS Âøh¯ÎUPÄ®. ÂÚõ Gs 24 &US
Pmhõ¯©õP Âøh¯ÎUPÄ®. 6x2=12

Note : Answer any six questions. Question No. 24 is compulsory.

16. JÎ-Ámh ªß-Û-ÓU-P® Gß-ÓõÀ GßÚ ?
What is corona discharge ?

17. PõÀ-Á-÷Úõ«m-h-›ß ªß-÷Úõmh Enº-v-ÓøÚ GÆ-ÁõÖ Av-P-›U-P-»õ® ?
How will you increase the current sensitivity of a galvanometer ?

18. J¸ E÷»õ-Pz-vß JÎ-ªß öÁÎ-÷¯ØÖ BØ-ÓÀ Gß-£øu Áøµ-¯-ÖUPÄ®. Auß
A»øPz u¸P.
Define work function of a metal. Mention its unit.

197
19.
79
Au AqU-P-¸-Âß Bµz-øuU PnU-Q-k-P.

197
Calculate the radius of Au nucleus.
79

20. ¤Í-ª[ Á»UøP Âv-ø¯U TÖ-P.
State Fleming’s right hand rule.

21. ©õ-`m-hÀ Gß-ÓõÀ GßÚ ?
What do you mean by Doping ?

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22. Ch¨-ö£-¯ºa] ªß-÷Úõm-h® Gß-ÓõÀ GßÚ ?
What is displacement current ?

23. ªß-uøh Gs Áøµ-¯-Ö.
Define electrical resistivity.

24. \© £UP •¨-£m-h-P® Jß-Ôß ]Ö-© vø\ ©õØ-ÓU ÷Põ-n® 408 GÛÀ, •¨-£m-h-P¨
ö£õ-¸-Îß JΠ»-PÀ Gs-ønU PnU-Q-k-P.
The angle of minimum deviation for the equilateral prism is 408. Find the refractive
index of the material of the prism.

£S-v - III / PART - III
SÔ¨¦ : GøÁ÷¯Ý® BÖ ÂÚõUPÐUS Âøh¯ÎUPÄ®. ÂÚõ Gs 33 &US
Pmhõ¯©õP Âøh¯ÎUPÄ®. 6x3=18
Note : Answer any six questions. Question No. 33 is compulsory.

25. ÷PõÍP Bi-°À f ©Ø-Ö® R &US Cøh-÷¯-¯õÚ öuõ-hº-¤øÚ Á¸-Â.
Derive the relation between f and R for a spherical mirror.

26. ªß- ÷ Úõm- h z- v Ø- S ®, Cʨ¦ vø\- ÷ Á- P z- v Ø- S ® Cøh- ÷ ¯- ¯ õÚ öuõ- h º- ¤ øÚ
Á¸--Â.
Obtain a relation between current and drift velocity.

27. JÎ-ªß ÂøÍ-Ä Âv-PøÍ Á›-ø\¨-£-kz-x-P.
List out the laws of photo electric effect.

28. ö£õx EªÌ¨-£õß {ø» Aø©¨-¤À NPN iµõß-]ì-h-›ß ªß-_ØÖ SÔ-±k £h®
Áøµ-P.
Draw the circuit diagram of NPN transistor in Common Emitter Configuration.

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29. ÷£õ-»-µõ´-iß £¯ß-PøÍ TÖ-P.
Give the uses of Polaroids.

30. öuõ-h-›-øn¨-¤À ªß-÷uU-Q-PÒ CønU-P¨-£-k®÷£õx ÂøÍ-²® öuõ-S£¯ß ªß
÷uU-Sz vÓ-ÝU-PõÚ \©ß-£õm-øh¨ ö£Ö-P.
Derive the expression for resultant capacitance, when capacitors are connected
in series.

31. øím-µ-áß Aq-Âß 5 &Áx _Ø-Ö¨-£õ-øu-°ß :

(i) ÷Põn E¢-u® ©Ø-Ö®

(ii) Av-¾ÒÍ G»Um-µõ-Ûß vø\-÷Á-P® BQ-¯-ÁØ-øÓU PnU-Q-k-P.
(h=6.6×10−34 Js ; m=9.1×10−31 kg)

Find the :

(i) Angular momentum

(ii) Velocity of the electron revolving in the 5 th orbit of hydrogen atom.
(h=6.6×10−34 Js ; m=9.1×10−31 kg)

32. Põ¢-u-Â-¯À »õ-µßì Âø\-°ß ]Ó¨-¤-¯À-¦-PøÍU SÔ¨-¤-k-P.
List out salient features of magnetic Lorentz force.

33. öuõ-hº RLC _Ø-ÔÀ EÒÍ ªß ys-i-°ß ªß-©-Ö¨¦, ªß ÷uU-Q-°ß ªß-©-Ö¨¦
©Ø-Ö® ªß-uøh BQ-¯øÁ •øÓ-÷¯ 184 Ω, 144 Ω ©Ø-Ö® 30 Ω GÛÀ _ØÔß ªß
Gvº¨- ø £U Põs- P . ÷©¾® ªß- Ú - Ê zu ÷ÁÖ- £ õk ©Ø- Ö ® ªß- ÷ Úõm- h ®
Cøh-°-»õÚ Pm-hU ÷Põ-nz-øu-²® PnU-Q-k-P.
Find the impedance of a series RLC circuit, if the inductive reactance, capacitive
reactance and resistance are 184 Ω, 144 Ω and 30 Ω respectively. Also calculate
the phase angle between voltage and current.

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5917 10

£S-v - IV / PART - IV
SÔ¨¦ : AøÚzx ÷PÒ-ÂPÐUS® Âøh¯ÎUPÄ®. 5x5=25

Note : Answer all the questions.

34. (A) J¸ •Ê Aø» v¸z- v - ° ß Aø©¨¦ ©Ø- Ö ® ö\¯À- £ - k ® Âuz- v øÚ
ÂÁ-›-U-P-Ä®.
AÀ-»-x
(B) ªß-©õØ-Ô-°ß Aø©¨¦ ©Ø-Ö® ö\¯À-£õmøh ÂÍU-S-P.
(a) Explain the construction and working of full wave rectifier.
OR
(b) Explain the construction and working of transformer.

35. (A) ªß C¸-•øÚ Jß-Ô-ÚõÀ HØ-£-k® {ø» ªß-Ú-Êz-uz-vØ-PõÚ ÷Põ-øÁ-ø¯¨
ö£Ö-P.
AÀ-»-x
(B) ¯[ Cµm-øh¨-¤ÍÄ B´-ÂÀ ö£Ó¨-£-k® £møh AP-»z-vØ-PõÚ ÷Põ-øÁ-ø¯¨
ö£Ö-P.
(a) Derive an expression for electrostatic potential due to an electric dipole.
OR
(b) Obtain the equation for bandwidth in Young’s Double Slit Experiment.

36. (A) £¯m & \õ-Áºm Âv-ø¯ £¯ß-£-kzv ªß-÷Úõm-h® £õ-²® •i-Â-»õ }Í®
öPõsh ÷|º Phz- v - ¯ õÀ J¸ ¦Ò- Î - ° À HØ- £ - k ® Põ¢- u ¨ ¦»z- v Ø- P õÚ
÷Põ-øÁ-ø¯¨ ö£Ö-P.
AÀ-»-x
(B) -øím-µ-áß Aq-Âß {Ó-©õø» öuõ-hº-PøÍ ÂÍU-S-P.
(a) Using Biot-Savart Law deduce the relation for the magnetic field at a point
due to an infinitely long straight conductor carrying current.
OR
(b) Discuss the spectral series of hydrogen atom.

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37. (A) (i) ]Ó¨-¦ X -Pvº {Ó-©õ-ø»ø¯ GÆ-ÁõÖ |õ® ö£Ö-Q-÷Óõ® ?
(ii) 20,000 V •kUS ªß- Ú - Ê z- u ® EÒÍ X - Pvº- SÇõ- ° À C¸¢x
öÁÎÁ¸® X - Pvº-P-Îß öÁmk Aø»-}Í® ©Ø-Ö® öÁmk Avº-öÁs
BQ-¯-Á-ØøÓU PnU-Q-kP.
AÀ-»-x
(B) {Ó-©õø» Gß-ÓõÀ GßÚ ? öÁÎ-Âk {Ó-©õ-ø»-°ß ÁøP-P-øÍ ÂÍUPÄ®.
(a) (i) How do we obtain characteristic X-ray spectra ?
(ii) Calculate the cut-off wavelength and cut-off frequency of X-rays from
an X-ray tube of accelerating potential 20,000 V.
OR
(b) What is spectrum ? Explain the types of emission spectrum.

38. (A) ö»ßì E¸-ÁõU-S-£-Á-›ß \©ß-£õm-iøÚ Á¸-Â.
AÀ-»-x
(B) ÷ÁõÀm «m- h øµ £¯ß- £ - k zv ªß- P - » zvß AP ªß- u - ø hø¯ Põs- £ øu
ÂÍU-S-P.
(a) Obtain Lens maker’s formula.
OR
(b) Explain the determination of the internal resistance of cell using voltmeter.

-o0o-

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