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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 மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications மின்னணு செலுத்தல் முறைகள் Sample Question Papers Study Material - QB365 Set A

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TN 12th Computer Applications மின் - வணிகம் Sample Question Papers Study Material - QB365 Set A

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12th Standard Physics English Medium Free Online Test Book Back 1 mark questions with Answer Key

Published on: 12/10/2020

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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Std: 12th Standard - Physics

chapter: - Model Question paper

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Questions:

Multiple Choice Question

25 x 1 = 25

The technology used for stopping the brain from processing pain is _____.

(a)

Precision medicine

(b)

Wireless brain sensor

(c)

Virtual reality

(d)

Radiology

“Sky wax” is an application of nano product in the field of _____.

(a)

Medicine

(b)

Textile

(c)

Sports

(d)

Automotive industry

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal is called ______.

(a)

Amplitude modulation

(b)

Frequency modulation

(c)

Phase modulation

(d)

Pulse width modulation

If a positive half-wave rectified voltage is fed to a load resistor, for which part of a cycle there will be current flow through the load?

(a)

0⁰–90⁰

(b)

90⁰–180⁰

(c)

0⁰–180⁰

(d)

0⁰–360⁰

The half-life period of a radioactive element A is same as the mean life time of another radioactive element B. Initially both have the same number of atoms. Then _____.

(a)

A and B have the same decay rate initially

(b)

A and B decay at the same rate always

(c)

B will decay at faster rate than A

(d)

A will decay at faster rate than B

The ratio between the radius of first three orbits of hydrogen atom is _____.

(a)

1:2:3

(b)

2:4:6

(c)

1:4:9

(d)

1:3:5

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)

A only

(b)

both A and B

(c)

all these metals

(d)

none

Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 eV, then the ratio of maximum speeds of emitted electrons in the two cases will be _____.

(a)

1:4

(b)

1:3

(c)

1:1

(d)

1:9

The wave associated with a moving particle of mass 3 x 10^–6 g has the same wavelength as an electron moving with a velocity 6 x 10⁶ ms^-1. The velocity of the particle is _____.

(a)

1.82 x 10^-18ms^-1

(b)

9 x 10^-2ms^-1

(c)

3 x 10^-31ms^-1

(d)

1.82 x 10^-15ms^-1

10.

Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are _____.

(a)

5I and I

(b)

5I and 3I

(c)

9I and I

(d)

9I and 3I

11.

Stars twinkle due to, ______.

(a)

reflection

(b)

total internal reflection

(c)

refraction

(d)

polarisation

12.

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?

(a)

30°

(b)

45°

(c)

60°

(d)

90°

13.

A bar magnet of length l and magnetic moment p_m is bent in the form of an arc as shown in Figure. The new magnetic dipole moment will be

(a)

p_m

(b)

\(\frac{3}{\pi} p_{m}\)

(c)

\(\frac{2}{\pi} p_{m}\)

(d)

\(\frac{1}{2} p_{m}\)

14.

Three wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semi-circle and the third one is a square. They are placed in a uniform magnetic field and same electric current is passed through them. Which of the following loop configuration will experience greater torque?

(a)

Circle

(b)

Semi-circle

(c)

Square

(d)

All of them

15.

In a series RL circuit, the resistance and inductive reactance are the same. Then the phase difference between the voltage and current in the circuit is

(a)

\(\frac{\pi}{4}\)

(b)

\(\frac{\pi}{2}\)

(c)

\(\frac{\pi}{6}\)

(d)

zero

16.

When the current changes from +2A to −2A in 0.05 s, an emf of 8 V is induced in a coil. The co-efficient of self-induction of the coil is

(a)

0.2H

(b)

0.4H

(c)

0.8H

(d)

0.1H

17.

If E = E_o sin[10⁶ x -ωt] be the electric field of a plane electromagnetic wave, the value of ω is_____.

(a)

0.3 x 10⁻¹⁴ rad s⁻¹

(b)

3 x 10⁻¹⁴ rad s⁻¹

(c)

0.3 x 10¹⁴ rad s⁻¹

(d)

3 x 10¹⁴ rad s^-1

18.

During the propagation of electromagnetic waves in a medium __________________.

(a)

electric energy density is double of the magnetic energy density

(b)

electric energy density is half of the magnetic energy density

(c)

electric energy density is equal to the magnetic energy density

(d)

both electric and magnetic energy densities are zero

19.

Which of the following is false for electromagnetic waves

(a)

transverse

(b)

non-mechanical waves

(c)

longitudinal

(d)

produced by accelerating charges

20.

Three capacitors are connected in triangle as shown in the figure. The equivalent capacitance between the points A and C is

(a)

1μF

(b)

2μF

(c)

3μF

(d)

\(\frac{1}{4}\)μF

21.

An electric field \(\vec { E } =10x\hat { i } \) exists in a certain region of space. Then the potential difference V = V_o – V_A, where V_o is the potential at the origin and V_A is the potential at x = 2 m is _____.

(a)

10 V

(b)

-20 V

(c)

+20 V

(d)

-10 V

22.

Four Gaussian surfaces are given below with charges inside each Gaussian surface. Rank the electric flux through each Gaussian surface in increasing order.

(a)

D < C < B < A

(b)

A < B = C < D

(c)

C < A = B < D

(d)

D > C > B > A

23.

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is ______.

(a)

0.2 Ω

(b)

0.5 Ω

(c)

0.8 Ω

(d)

1.0 Ω

24.

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 ______.

(a)

14 A

(b)

8 A

(c)

10 A

(d)

12 A

25.

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

(a)

\(\pi \Omega\)

(b)

\(\frac{\pi}{2}\Omega\)

(c)

2\(\pi \Omega\)

(d)

\(\frac{\pi}{4}\Omega\)

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Answers Key:

Multiple Choice Question

25 x 1 = 25

Medical virtual reality is effectively used to stop the brain from processing pain and cure soreness.

(b)
Frequency modulation

T_A1/2 = ፒ_B
\(\frac{0.6931}{\lambda_{\mathrm{A}}}=\frac{1}{\lambda_{\mathrm{B}}} \)
\(\lambda_{\mathrm{B}}=\frac{\lambda_{\mathrm{A}}}{0.6931}=1.44 \lambda_{\mathrm{A}}\)
Hence, B will decay at faster rate than A

r_n ∞ n²
r₁: r₂: r₃ = 1: 4: 9

\(E=\frac{12400 \stackrel{o}A}{4100 \stackrel{o}A}=3.02 eV\)

K.E= hv - Φ
K.E₁ = 0.9 - 0.6 = 0.3 eV
K.E₂ = 3.3 - 0.6 = 2.7 ev
K.E ∝ v²
\(\frac{0.3}{2.7}=\frac{v^2_1}{v^2_2} \)
\(\frac{v^1}{v^2} =\frac{1}{3}\)

\(\lambda_{\mathrm{i}} \frac{1}{\mathrm{mv}} \)
\(\frac{\lambda_p}{\lambda_e} =\frac{m_e v_e}{m_P v_P} \)
\(1 =\frac{9.1 \times 10^{-31} \times 6 \times 10^6}{3 \times 10^{-9} \times v_p} \)
\(\mathrm{v}_{\mathrm{p}} =9.1 \times 10^{-16} \times 2 \)
\(\mathrm{v}_{\mathrm{p}} =18.2 \times 10^{-16} \)
\(\mathrm{v}_{\mathrm{p}} =1.82 \times 10^{-15} \mathrm{~m} \mathrm{~s}^{-1}\)

10.

I = l₁ + l₂ + 2\(\sqrt{I_1I_2}\)cos θ
If cos θ = cos 0 = l, I is max
= I+ 4I + 2\(\sqrt{41^2}\) cos 0
= 5I + 4I = 91
If cos π = -1, I is min
I_min = I + 4I + 2\(\sqrt{41^2}\) cos π
= 5I + 4I(-1)
= 5I + 4I = I
(I_max, I_min)= (9I, I)

11.

12.

\(tan \ I=\frac{B_V}{B_H}=1\)
∴ I = 45^o

13.

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 = \(\frac{3}{\pi}p_m\)

14.

(a)
Circle

15.

In RL circuit, tanΦ = \(\frac{X_l}{R}\)
If R = X₁, then tanΦ = \(\frac{X_l}{X_l}=1\)
∴ Φ = tan^-1(1)=\(\frac{\pi}{4}\)
∴ Phase difference \(=\frac{\pi}{4}\)

16.

\(\text {emf } e=8 \mathrm{~V} \)
\(d I=I_1-I_0=2-(-2)=4 \mathrm{~A} \)
\(\text {dt }=0.05 \mathrm{~s} \)
\(L=\frac{-e}{d I / d t}=\frac{-8}{4 / 0.05} \)
\(=\frac{-8 \times 0.05}{4}=\frac{-0.40}{4} \)
=-0.1 H
-ve sign indicates that self-induced emf always opposes the current w.r.t. time.

17.

E = E_o sin(kx – ωt)
ω = ck
ω = 3 x 10⁸ x 10⁶
ω = 3 x 10¹⁴ rad s^-1

18.

19.

20.

\(\frac{1}{C_s}=\frac{1}{2}+\frac{1}{2}=1 \ μF\)
C_p= 1 + 1 = 2 μF

21.

\(\vec {E}\) = 10x\(\hat{i},\) when x = 2 m
\(\vec {E}\) = 10 x 2 x \(\hat{i}\) = 20\(\hat{i}\)
Since, \(E=\frac{-dV}{dx}\therefore V=+20 V\)

22.

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

23.

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

24.

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

25.

Total length = 2πr = 2π
∴ Resistance of each segment = 2π/2 = π Ω