12th Standard Syllabus & Materials
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TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A
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TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A
Published on: 28/11/2025
Download Tamil Nadu 12th Standard Physics question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
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1.
In an unbiased p-n junction, the majority charge carriers (that is, holes) in the p-region diffuse into n-region because of ______.
the potential difference across the p-n junction
the higher hole concentration in p-region than that in n-region
the attraction of free electrons of n-region
the higher concentration of electrons in the n-region than that in the p-region
2.
Fraunhofer lines are an example of ______ spectrum.
line emission
line absorption
band emission
band absorption
3.
An e.m. wave is propagating in a medium with a velocity \(\vec{v}=v \hat{i}\). The instantaneous oscillating electric field of this e.m. wave is along + y-axis, then the direction of oscillating magnetic field of the e.m. wave will be along _____.
–y direction
–x direction
+z direction
–z direction
4.
The gravitational waves were theoretically proposed by _____.
Conrad Rontgen
Marie Curie
Albert Einstein
Edward Purcell
5.
The technology used for stopping the brain from processing pain is _____.
Precision medicine
Wireless brain sensor
Virtual reality
Radiology
6.
7.
The method of making nanomaterial by assembling the atoms is called _____.
Top down approach
Bottom up approach
Cross down approach
Diagonal approach
8.
The blue print for making ultra durable synthetic material is mimicked from _____.
Lotus leaf
Morpho butterfly
Parrot fish
Peacock feather
9.
The output of the following circuit is 1 when the input ABC is______.
101
100
110
010
10.
The zener diode is primarily used as ______.
Rectifier
Amplifier
Oscillator
Voltage regulator
11.
If a small amount of antimony (Sb) is added to germanium crystal,______.
it becomes a p-type semiconductor
the antimony becomes an acceptor atom
there will be more free electrons than hole in the semiconductor
its resistance is increased
12.
The barrier potential of a silicon diode is approximately, ______.
0.7 V
0.3 V
2.0 V
2.2 V
13.
14.
The nucleus is approximately spherical in shape. Then the surface area of nucleus having mass number A varies as _____.
A2/3
A4/3
A1/3
A5/3
15.
If the nuclear radius of 27Al is 3.6 fermi, the approximate nuclear radius of 64Cu, in femi is _____.
2:4
1.2
4.8
3.6
16.
17.
In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to _____.
h
\(\frac{h}{\pi}\)
\(\frac{4h}{\pi}\)
\(\frac{2h}{\pi}\)
18.
The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metal/metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are _____.
A only
both A and B
all these metals
none
19.
The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is _____.
4125 \(\mathring { A } \)
3750\(\mathring { A } \)
6000\(\mathring { A } \)
2062.5\(\mathring { A } \)
20.
If the mean wavelength of light from sun is taken as 550 nm and its mean power as 3.8 x 1026 W, then the number of photons emitted per second from the sun is of the order of _____.
1045
1042
1054
1051
21.
22.
When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is \(\frac{V}{4}\). The threshold wavelength for the metallic surface is _____.
4λ
5λ
\(\frac{5}{2}λ\)
3λ
23.
When light is incident on a soap film of thickness 5 x 10–5 cm, the wavelength of light reflected maximum in the visible region is 5320 Å. Refractive index of the film will be, _____.
1.22
1.33
1.51
1.83
24.
In a Young’s double-slit experiment, the slit separation is doubled. To maintain the same fringe spacing on the screen, the screen-to-slit distance D must be changed to, _____.
2D
\(\frac{D}{2}\)
\(\sqrt{2}\)D
\(\frac{D}{\sqrt2}\)
25.
Stars twinkle due to, ______.
reflection
total internal reflection
refraction
polarisation
26.
An object is placed in front of a convex mirror of focal length off and the maximum and minimum distance of an object from the mirror such that the image formed is real and magnified.
2f and c
c and \(\infty\)
f and O
None of these
27.
A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 cm in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is, ______.
2.5 cm
5cm
10 cm
15cm
28.
The vertical component of Earth’s magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?
30°
45°
60°
90°
29.
The BH curve for a ferromagnetic material is shown in the figure. The material is placed inside a long solenoid which contains 1000 turns/cm. The current that should be passed in the solenoid to demagnetize the ferromagnet completely is _____.
1.00 m A
1.25 mA
1.50 mA
1.75 mA
30.
A bar magnet of length l and magnetic moment pm is bent in the form of an arc as shown in Figure. The new magnetic dipole moment will be
pm
\(\frac{3}{\pi} p_{m}\)
\(\frac{2}{\pi} p_{m}\)
\(\frac{1}{2} p_{m}\)
31.
A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is nearly ____.
1.0 A m2
1.2 A m2
0.5 A m2
0.8 A m2
32.
A particle having mass m and charge q accelerated through a potential difference V. Find the force experienced when it is kept under perpendicular magnetic field \(\vec { B } \).
\(\sqrt { \frac { 2{ q }^{ 3 }BV }{ m } } \)
\(\sqrt { \frac { { q }^{ 3 }{ B }^{ 2 }V }{ 2m } } \)
\(\sqrt { \frac { 2{ q }^{ 3 }{ B }^{ 2 }V }{ m } } \)
\(\sqrt { \frac { { 2q }^{ 3 }BV }{ { m }^{ 3 } } } \)
33.
\(\frac{20}{\pi^2}H\) inductor is connected to a capacitor of capacitance C. The value of C in order to impart maximum power at 50 Hz is
50 μF
0.5 μF
500 μF
5 μF
34.
In an oscillating LC circuit, the maximum charge on the capacitor is Q. The charge on the capacitor when the energy is stored equally between the electric and magnetic fields is
\(\frac{Q}{2}\)
\(\frac{Q}{\sqrt3}\)
\(\frac{Q}{\sqrt2}\)
Q
35.
In an electrical circuit, R, L, C, and AC voltage source are all connected in series. When L is removed from the circuit, the phase difference between the voltage and current in the circuit is \(\frac{\pi}{3}\). Instead, if C is removed from the circuit, the phase difference is again \(\frac{\pi}{3}\). The power factor of the circuit is
1/2
1/\(\sqrt2\)
1
\(\sqrt3\)/2
36.
A circular coil with a cross-sectional area of 4 cm2 has 10 turns. It is placed at the centre of a long solenoid that has 15 turns/cm and a cross-sectional area of 10 cm2. The axis of the coil coincides with the axis of the solenoid. What is their mutual inductance?
7.54 μH
8.54 μH
9.54 μH
10.54 μH
37.
An electron moves on a straight line path XY as shown in the figure. The coil abcd is adjacent to the path of the electron. What will be the direction of current, if any, induced in the coil?
The current will reverse its direction as the electron goes past the coil
No current will be induced
abcd
adcb
38.
Which of the following is NOT true for electromagnetic waves?
it transport energy
it transport momentum
it transport angular momentum
in vacuum, it travels with different speeds which depend on their frequency
39.
Consider an oscillator which has a charged particle oscillating about its mean position with a frequency of 300 MHz. The wavelength of electromagnetic waves produced by this oscillator is _____.
1 m
10 m
100 m
1000 m
40.
Which of the following is false for electromagnetic waves
transverse
non-mechanical waves
longitudinal
produced by accelerating charges
41.
Two points A and B are maintained at a potential of 7 V and -4 V respectively. The work done in moving 50 electrons from A to B is _______.
8.80 x 10-17 J
-8.80 x 10-17 J
4.40 x 10-17 J
5.80 x 10-17 J
42.
Two identical conducting balls having positive charges q1 and q2 are separated by a centre to centre distance r. If they are made to touch each other and then separated to the same distance, the force between them will be _____.
less than before
same as before
more than before
zero
43.
Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric flux through each Gaussian surface in increasing order.
D < C < B < A
A < B = C < D
C < A = B < D
D > C > B > A
44.
Which charge configuration produces a uniform electric field?
point charge
uniformly charged infinite line
uniformly charged infinite plane
uniformly charged spherical shell
45.
Two identical point charges of magnitude –q are fixed as shown in the figure below. A third charge +q is placed midway between the two charges at the point P. Suppose this charge +q is displaced a small distance from the point P in the directions indicated by the arrows, in which direction(s) will +q be stable with respect to the displacement?
A1 and A2
B1 and B2
both directions
No stable
46.
The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is ______.
0.2 Ω
0.5 Ω
0.8 Ω
1.0 Ω
47.
In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW are connected. The voltage of electric mains is 220 V. The maximum capacity of the main fuse of the building will be ______.
14 A
8 A
10 A
12 A
48.
A toaster operating at 240 V has a resistance of 120 Ω. The power is ______.
400 W
2 W
480 W
240 W
49.
A wire of resistance 2 ohms per meter is bent to form a circle of radius 1m. The equivalent resistance between its two diametrically opposite points, A and B as shown in the figure is
\(\pi \Omega\)
\(\frac{\pi}{2}\Omega\)
2\(\pi \Omega\)
\(\frac{\pi}{4}\Omega\)
50.
The following graph shows current versus voltage values of some unknown conductor. What is the resistance of this conductor?
2 ohm
4 ohm
8 ohm
1 ohm
1.
(d)
the higher concentration of electrons in the n-region than that in the p-region
2.
(b)
line absorption
3.
(c)
+z direction
4.
Albert Einstein theoretically proposed the existence of gravitational waves in the year 1915.
5.
Medical virtual reality is effectively used to stop the brain from processing pain and cure soreness.
6.
(c)
7.
There are two type of Synthesis of nano materials:
(i) Bottom up - Assembling atoms together.
(ii) Top down Breaking down bulk solid.
8.
Parrot fish's source of bite → mimic → Ultra durable synthetic material.
Lotus leaf surface → SEM → Self Cleaning Process
The scales on the wings of a morpho butterfly → mimic → Interaction of colours.
Peacock feathers → mimic → Glowing in different colours.
9.
A = 1, B = 0, C = 1
y = A + B, y = (A + B).C
y = (1 + 0).1 ⇒ y = 1
10.
(d)
Voltage regulator
11.
(c)
there will be more free electrons than hole in the semiconductor
12.
(a)
0.7 V
13.
(b)
14.
r ∝ A1/3
Surface Area = 4πr2
Hence, Surface Area ∝ A2/3
15.
\(r \propto A^{\frac{1}{3}} \)
\(\frac{r_{\mathrm{Cu}}}{\mathrm{r}_{\mathrm{Al}}}=\frac{\mathrm{A}_{\mathrm{Cu}}^\frac{1}{3}}{\mathrm{~A}_{\mathrm{Al}}^{\frac{1}{3}}}=\frac{4}{3} \)
\(\mathrm{r}_{\mathrm{Cu}}=\frac{4}{3} \times 3.6 \mathrm{~F}=4.8 \mathrm{~F}\)
16.
(b)
17.
\(L=\frac{nh}{2\pi}=\frac{4h}{2\pi}=\frac{2h}{\pi}\)
18.
\(E=\frac{12400 \stackrel{o}A}{4100 \stackrel{o}A}=3.02 eV\)
19.
\(\lambda_0 =\frac{h c}{\phi} \)
\(=\frac{6.626 \times 10^{-34} \times 3 \times 10^8}{3.313 \times 1.6 \times 10^{-19}} \)
\( =\frac{19.8782400}{5.3} \times 10^{-7} \)
\(\lambda_0 =3.750 \times 10^{-7} \simeq 3750 \stackrel{o}A\)
20.
\(\mathrm{P} =\frac{\mathrm{n}}{\mathrm{t}} \frac{\mathrm{hc}}{\lambda} \)
\(\frac{\mathrm{n}}{\mathrm{t}} =\frac{\mathrm{P} \lambda}{\mathrm{hc}} \)
\(\frac{\mathrm{n}}{\mathrm{t}} =\frac{3.8 \times 10^{26} \times 550 \times 10^{-9}}{6.6 \times 10^{-3} \times 3 \times 10^8}=1 \times 10^{-15}\)
21.
(b)
22.
\(\frac{\mathrm{hc}}{\lambda}=\phi+\mathrm{eV} \) .....(1)
\(\frac{\mathrm{hc}}{2 \lambda}=\phi+\frac{\mathrm{eV}}{4}\) .....(2)
multiply (2) eqn by 4
\(\frac{2 h c}{\lambda}=4 \phi+\mathrm{eV}\) .....(3)
subtract eqn (1) from (3), we get
\(\frac{ h c}{\lambda}=3 \phi \Rightarrow \phi = \frac{ h c}{3\lambda}\)
\(\frac{ h c}{\lambda_o}=\frac{ h c}{3\lambda}\)
⋋o = 3⋋
23.
2n t cos r = (2m + 1) \(\frac{\lambda}{2}\)
For maximum
m = 2 (For visible region), n - refractive index.
cos r = cos 0 = 1
t = 5 x 10-5 x 10-2 = 5 x 10-7 m
\(n=\frac{(2m+1)\frac{\lambda}{2}}{2t}=\frac{5\lambda}{2 \times 2 \times t}\)
\(=\frac{5 \times5320\times10^{-10}}{4 \times 5 \times 10^{-7}}\)
\(=\frac{5 \times5320\times10^{-10}}{20}=1330 \times 10^3\)
n = 1.330
24.
d' = 2d, β' = β, D' = ?
W.K.T, Fringe width
\(\beta = \frac{D\lambda}{d} \Rightarrow D' = \frac{Dd'}{d}\)
\(D' = \frac{D2d}{d}=2D\)
25.
(c)
refraction
26.
Convex Mirror is diverging in nature and for all positions of objects, convex mirror forms virtual and erect image.
27.
At end A,
\(\frac{1}{f} =\frac{1}{u_A}+\frac{1}{v_A} \)
\(\therefore \frac{1}{v_A} =\frac{1}{-10}-\frac{1}{-20} \)
\(\frac{1}{v_A} =-\frac{1}{10}+\frac{1}{20}=\frac{-2+1}{20}=-\frac{1}{20} \)
\(v_A =-20 \mathrm{~cm} \)
\(\left|v_{\wedge}\right|=20 \mathrm{~cm}\)
At end B,
\(\frac{1}{f} =\frac{1}{u_B}+\frac{1}{v_B} \)
\(\frac{1}{v_B} =\frac{1}{f}-\frac{1}{u_B}, \)
\(u_B =-30 \mathrm{~cm} \)
\(\frac{1}{v_B} =-\frac{1}{10}+\frac{1}{30} \)
\(=\frac{-3+1}{30}=\frac{-2}{30}=\frac{-1}{15} \)
\(v_B =-15 \mathrm{~cm} \)
\(\left|v_B\right| =15 \mathrm{~cm} \)
\(\therefore \quad\left|\mathrm{v}_{\mathrm{A}}\right|-\left|\mathrm{v}_{\mathrm{B}}\right| \) is the length of the image
= 20 - 15 = 5 cm
28.
\(tan \ I=\frac{B_V}{B_H}=1\)
∴ I = 45o
29.
(c)
1.50 mA
30.
Magnetic moment,
p'm = ml
From figure, \(l=\frac{\pi r}{3}\)
\(\therefore r=\frac{3l}{\pi}\)
∴ New magnetic moment,
p'm = m x r
\(=m\times \frac{3l}{\pi}=\frac{3}{\pi}ml\)
∴ p'm = \(\frac{3}{\pi}p_m\)
31.
Dipole moment, \(\vec{p}_m=n\times I\times\vec{A}\)
\(\vec{p}_m\) = 50 x 3 x 3.14 x 25 x 10-4 ≈ 1.2 A m2
32.
Lorentz force F = Bqv
Energy w = qV
Energy is equal to kinetic energy,
\(qV=\frac{1}{2}mv^2\)
\(v=\sqrt { \frac {2qV }{ m } } \)
\(\therefore Lorentz \ force \ F= Bq\times \sqrt \frac{2qV}{m}=\sqrt { \frac { 2{ B }^{ 2 }{ q }^{ 3 }V }{ m } } \)
33.
\(L=\frac{20}{\pi^2} \mathrm{H}, \mathrm{f}=50 \mathrm{~Hz} \)
\(f=\frac{1}{2 \pi \sqrt{L C}} \)
\(50=\frac{1}{2 \pi \sqrt{\frac{20}{\pi^2} \times C}} \)
\(50=\frac{1}{2 \times \sqrt{20 C}} \)
\(\therefore(50)^2=\frac{1}{4 \times 20 C} \)
\(\therefore C=\frac{1}{2500 \times 4 \times 20}=5 \times 10^{-6}=5 \mu \mathrm{F}\)
34.
\(Q_{midpoint}=\frac{Q}{\sqrt{1^2+1^2}}=\frac{Q}{\sqrt2}\)
35.
\(\Phi = \frac{\pi}{3}-\frac{\pi}{3}=0 \)
Power factor = cosФ = cos 0 = 1
36.
\(A_1 =4 \times 10^{-4} \mathrm{~m}^2 \)
\(N_1 =10 \text { turns } \)
\(A_2 =4 \times 10^{-4} \mathrm{~m}^2 \)
\(N_2 =15 \times 10^{-}=1500 \mathrm{turn} / \mathrm{m} \)
\(\phi =B_2 A_2=\left(\mu_0 \mathrm{n}_2 I_2\right) \mathrm{A}_1 \)
\(Where, \mathrm{n}_2=\frac{\mathrm{N}_2}{l}=1500 \mathrm{turn} / \mathrm{m}\)
The mutual Inductance is,
\(M =\frac{N_1 o_{12}}{I_2}=\mu_0 n_2 N_1 A_1 \)
\(=4 \pi \times 10^{-7} \times 1500 \times 10 \times 4 \times 10^{-4} \)
\(=7.54 \times 10^{-6} \mathrm{H}=7.54 \mu \mathrm{H}\)
37.
The direction of conventional current is always opposite to the direction of flow of electrons.
38.
(d)
in vacuum, it travels with different speeds which depend on their frequency
39.
ג = \(\frac{c}{f}=\frac{3 \times10^8}{300 \times 10^6}=1 m\)
40.
(c)
longitudinal
41.
W = qV
V = 7 - (-4) = 11 V
q = ne = 50 x 1.6 x 10-19 = 8 x 10-18C
W = 8 x 10-18 x 11 = 88 x 10-18 = 8.8 x 10-17]
42.
Force ∝ charge
After the separation, the magnitude of charge will be increased. So the force will be more than before.
43.
The electric flux of D is less than that of C
The electric flux of C is less than that of B
The electric flux of B is less than that of A
44.
(c)
uniformly charged infinite plane
45.
The charge + q will be stable between B1 and B2 with respect to the displacement.
46.
I = 0.2 A, R = 10 Ω, E = 2.1 V
\(I=\frac{ɛ}{R+r}\)
\(0.2=\frac{2.1}{10+r}\)
0.2 x (10 + r) = 2.1
2 + 0.2 r = 2.1
0.2 r = 2.1 - 2 = 0.1
Internal resistance, \(r=\frac{0.1}{0.2}=\frac{1}{2}\)
r = 0.5 Ω
47.
Total power = 15 x 40 + 5 x 100 + 5 x 80 + 1000
= 600 + 500 + 400 + 1000
= 2500 W
P = VI, V = 220 V
\(I=\frac{P}{V}=\frac{2500}{220}=11.363 \ A\)
≃ 12 A
48.
\(P=\frac{V^2}{R}=\frac{240 \times 240}{120}=480 \ W\)
49.
Total length = 2πr = 2π
∴ Resistance of each segment = 2π/2 = π Ω
50.
Resistance, \(R=\frac{V}{I}=\frac{4}{2}=2 \ ohm\)
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