12th Standard Physics English Medium Free Online Test 1 mark questions 2020 | QB365

12th Standard Syllabus & Materials

12th Standard

TN 12th Computer Applications மின்னணு தரவு பரிமாற்றம் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications மின் - வணிக பாதுகாப்பு அமைப்புகள் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

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

NEW

12th Standard

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

NEW

12th Standard

TN 12th Computer Applications திறந்த மூல கருத்துருக்கள் Sample Question Papers Study Material - QB365 Set A

NEW

12th Standard

TN 12th Computer Applications வலையமைப்பு வடமிடல் Sample Question Papers Study Material - QB365 Set A

12th Standard Physics English Medium Free Online Test 1 mark questions 2020

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.

Questions + Answers key

Take MCQ Physics Test

QB365 Student Learing Managemnet System

Std: 12th Standard - Physics

chapter: - Model Question paper

Visit QB365-SLMS - https://www.qb365.in/slms/ Complete Questions and Answers

Questions:

Multiple Choice Question

25 x 1 = 25

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

(a)

Medicine

(b)

Textile

(c)

Sports

(d)

Automotive industry

The frequency range of 3 MHz to 30 MHz is used for ______.

(a)

Ground wave propagation

(b)

Space wave propagation

(c)

Sky wave propagation

(d)

Satellite communication

If the input to the NOT gate is A = 1011, its output is ______.

(a)

0100

(b)

1000

(c)

1100

(d)

0011

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 ratio of the wavelengths radiation emitted for the transition from n = 2 to n = 1 in Li⁺⁺, He⁺and H is _____.

(a)

1:2:3

(b)

1:4:9

(c)

3:2:1

(d)

4:9:36

Atomic number of H-like atom with ionization potential 122.4 V for n = 1 is _____.

(a)

(b)

(c)

(d)

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 _____.

(a)

4λ

(b)

5λ

(c)

\(\frac{5}{2}λ\)

(d)

3λ

Light transmitted by Nicol prism is, _____.

(a)

partially polarised

(b)

unpolarised

(c)

plane polarised

(d)

elliptically polarised

Stars twinkle due to, ______.

(a)

reflection

(b)

total internal reflection

(c)

refraction

(d)

polarisation

10.

For light incident from air on a slab of refractive index 2, the maximum possible angle of refraction is, ______.

(a)

30^o

(b)

45^o

(c)

60^o

(d)

90^o

11.

The current through a solenoid of length 0.5 m with 400 turns produces a magnetic field 10^-3 tesla. The current is _______

(a)

(b)

(c)

(d)

0.5 mA

12.

Two T.G's having reduction factor K₁ and K₂ are connected series and give deflections θ₁and θ₂ respectively. Then K₁ : K₂_____________________.

(a)

θ ₁ : θ ₂

(b)

tanθ₁ : tanθ₂

(c)

θ ₂ : θ ₁

(d)

tanθ₂ : tanθ₁

13.

Near a charged object A another earthed object B is placed. Charges are induced on B. If B is removed. After that the charge on A ________.

(a)

remains the same

(b)

decreases

(c)

increases

(d)

becomes zero

14.

In an electric circuit fuse wire is connected in ________________.

(a)

parallel

(b)

star connection

(c)

delta connection

(d)

series

15.

A condenser of 2μF capacitance is charged steadily from 0 to 5 coulomb. Which of the following graphs correctly represents the variation of potential difference across its plates with respect to the charge on the condensor [Q = C V ]

(a)

(b)

(c)

(d)

16.

The given figure is a plot of lines of force due to two charges q₁ & q₂ find out the sign of charges

(a)

both negative

(b)

both positive

(c)

upper positive and lower negative

(d)

upper negative and lower positive

17.

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 _____.

(a)

1.00 m A

(b)

1.25 mA

(c)

1.50 mA

(d)

1.75 mA

18.

An electron moves in a straight line inside a charged parallel plate capacitor of uniform charge density σ. The time taken by the electron to cross the parallel plate capacitor undeflected when the plates of the capacitor are kept under constant magnetic field of induction \((\vec{B})\) is

(a)

\({ \varepsilon }_{ ° }\frac { elB }{ \sigma } \)

(b)

\({ \varepsilon }_{ ° }\frac { lB }{ \sigma {l} } \)

(c)

\({ \varepsilon }_{ ° }\frac { lB }{ {e}\sigma } \)

(d)

\({ \varepsilon }_{ ° }\frac { lB }{ \sigma } \)

19.

The flux linked with a coil at any instant t is given by \(\Phi\)_B = 10t²− 50t + 250. The induced emf at t = 3s is

(a)

−190 V

(b)

−10 V

(c)

10 V

(d)

190 V

20.

A radiation of energy E falls normally on a perfectly reflecting surface. Th e momentum transferred to the surface __________________.

(a)

\(\frac{E}{c}\)

(b)

2\(\frac{E}{c}\)

(c)

(d)

\(\frac { E }{ { c }^{ 2 } } \)

21.

Which of the following is false for electromagnetic waves

(a)

transverse

(b)

non-mechanical waves

(c)

longitudinal

(d)

produced by accelerating charges

22.

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

23.

Which charge configuration produces a uniform electric field?

(a)

point charge

(b)

uniformly charged infinite line

(c)

uniformly charged infinite plane

(d)

uniformly charged spherical shell

24.

A wire connected to a power supply of 230 V has power dissipation P₁. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case power dissipation is P₂. The ratio \(\frac{P_2}{P_1}\) is ______.

(a)

(b)

(c)

(d)

25.

A toaster operating at 240 V has a resistance of 120 Ω. The power is ______.

(a)

400 W

(b)

2 W

(c)

480 W

(d)

240 W

Visit QB365-SLMS - https://www.qb365.in/slms/

Answers Key:

Multiple Choice Question

25 x 1 = 25

Ground wave propagation: frequency less than 2 MHz
Sky wave propagation: 3 to 30 MHz
Space wave propagation: Above 30 MHz to 400 GHz
Satellite communication: uplink communication 6 GHz band downlink communication 4 GHz band

\(y=\overline{A}=\overline{1011}=0100\)
The Boolean expression for NOT gate, \(y=\bar{A}\)

\(\frac{1}{\lambda}=\mathrm{RZ}^2\left[\frac{1}{\mathrm{n}_1^2}-\frac{1}{\mathrm{n}_2^2}\right] \)
\(\frac{1}{\lambda}=\mathrm{RZ} ^2\left[\frac{1}{1}-\frac{1}{4}\right]=\frac{3}{4} \mathrm{RZ}^2 \)
\(\lambda \propto \frac{1}{Z^2} \)
\(\lambda_{\mathrm{Li}}: \lambda_{\mathrm{H} c}: \lambda_{\mathrm{H}}=\frac{1}{9}: \frac{1}{4}: \frac{1}{1}=4: 9: 36\)

\(V_{ionisation}=\frac{13.6}{n^2}Z^2 volt\)
\(Z=\sqrt\frac{V\times n^2}{13.6}=\sqrt\frac{122.4 \times I^2}{13.6}=\sqrt{9}=3\)

\(\frac{\mathrm{hc}}{\lambda}=\phi+\mathrm{eV} \) .....(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⋋

10.

(a)
30^o

11.

12.

(d)
tanθ₂ : tanθ₁

13.

(a)
remains the same

14.

(d)
series

15.

16.

(a)
both negative

17.

18.

Electric field between the plates \(= \frac{σ}{ε_0}\)
Electric force on an electron \(= e\frac{σ}{ε_0}\)
Magnetic force on an electron, F = BIl
But, \(I= \frac{e}{t}\)
∵Electron moves in a straight line. So,
E_F= M_F
\(e\frac{σ}{ε_0}=B(\frac{e}{t})l\)
\(\therefore t = ε_0\frac{lB}{σ}\)

19.

\(\phi_B =10 t^2-50 t+250 \)
\(e =\frac{-d \phi_B}{d t} \)
\(=\frac{-d}{d t}\left(10 t^2-50 t+250\right) \)
=-(20 t - 50)
=-20 t + 50
When, t = 3 s, e =-20(3) + 50 = -60 + 50
e = -10V

20.

(b)
2\(\frac{E}{c}\)

21.

22.

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

23.

24.

\(\mathrm{V}=230 \mathrm{~V} \)
\(P=\frac{V^2}{R} \text { since } \mathrm{V} \text { is same } \mathrm{P} \propto \frac{1}{R} \)
\(\frac{1}{R_2}=\frac{1}{\frac{R_1}{2}}+\frac{1}{\frac{R_1}{2}}=\frac{2}{R_1}+\frac{2}{R_1}=\frac{2+2}{R_1} \)
\(\frac{1}{R_2}=\frac{4}{R_1} \)
\(\therefore R_2=\frac{R_1}{4} \)
\(R_1=4 R_2 \)
\(\therefore \frac{P_2}{P_1}=\frac{R_1}{R_2}=\frac{4 R_2}{R_2}=4\)

25.

\(P=\frac{V^2}{R}=\frac{240 \times 240}{120}=480 \ W\)