12th Standard Physics English Medium Free Online Test 1 mark questions 2020 - Part Seven | 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 - Part Seven

Published on: 12/10/2020

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

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

Two plane mirrors are parallel to each other and spaced 20cm apart. An object is kept in between them at 15cm from A. out of the following at which point on the image is not formed in mirror A (distance measured from mirror A) ___________.

(a)

15 cm

(b)

25 cm

(c)

45 cm

(d)

55 cm

__________ Scanning Electron Micrograph (SEM) showing the nano structures on the surface of a leaf from a lotus plant

(a)

Parrot fish

(b)

Morpho butterfly

(c)

Lotus leaf surface

(d)

Peacock feathers

Wavelength of X-rays is ______ the wavelength of visible light

(a)

smaller than

(b)

greater than

(c)

negligible when compared to

(d)

equal to

The transmitter in a RADAR is a high power ________.

(a)

cyclotron oscillator

(b)

magnetron oscillator

(c)

Hartley oscillator

(d)

simple harmonic oscillator

In a television, the picture signals are _________ modulated.

(a)

amplitude

(b)

frequency

(c)

phase

(d)

pulse-code

In burglar-alarm, ________ is continuously made to fall' on the photo cell.

(a)

radio waves

(b)

UV rays

(c)

visible light

(d)

\(\gamma\)-rays

Photoelectric cells are of _______ types.

(a)

two

(b)

three

(c)

four

(d)

five

In a p-n junction diode _________________.

(a)

the current in the reverse biased condition is generally very small

(b)

the current in the reverse biased condition is small but the forward biased current is independent of the biased voltage

(c)

the reverse biased current is strongly dependent on the applied bias voltage.

(d)

the forward biased current is very small in comparison to reverse biased current

Energy of each photon is ______

(a)

\(\frac{2}{3}\) hv

(b)

3 hv

(c)

2 hv

(d)

10.

Light exhibits _______ duality.

(a)

particle-wave

(b)

solid-liquid

(c)

liquid-gas

(d)

gas-plasma

11.

The ground-state energy of hydrogen atom is ____________ eV

(a)

-13.6

(b)

-18.7

(c)

18.6

(d)

\(\frac{1}{13.6}\)

12.

In a discharge tube, the source of positive rays is ________________.

(a)

cathode

(b)

anode

(c)

gas atoms present in the discharge tube

(d)

fluorescent screen

13.

The specific characteristic of a common emitter amplifier is _______________.

(a)

High input resistance

(b)

Low power gain

(c)

Signal phase reversal

(d)

Low current gain

14.

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

15.

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)

increase by 2 times

(b)

decrease by 2 times

(c)

decrease by 4 times

(d)

increase by 4 times

16.

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, ______.

(a)

2.5 cm

(b)

5cm

(c)

10 cm

(d)

15cm

17.

The direction of magnetic field close to a straight conductor carrying current will be _______________.

(a)

along the length of the conductor

(b)

radially outward

(c)

circular in a plane perpendicular to the conductor

(d)

helical

18.

The phase difference between VL and Vc is _________________

(a)

2π

(b)

π/2

(c)

π/4

(d)

19.

Which of the following has negative temperature coefficient of resistance?

(a)

copper

(b)

tungsten

(c)

carbon

(d)

silver

20.

Four plates each of area N and inferplate separation 'd' are placed as shown in figure. The two inner plates are connected to the point 'B' and outer to point 'A'. What is equivalent capacitance?

(a)

\(\frac { { \varepsilon }_{ 0 }A }{ d } \\ \)

(b)

\(\frac { {2 \varepsilon }_{ 0 }A }{ d } \\ \)

(c)

\(\frac { {3 \varepsilon }_{ 0 }A }{ d } \\ \)

(d)

\(\frac { {4 \varepsilon }_{ 0 }A }{ d } \\ \)

21.

The value of constant 'K' in coulomb law is _____________.

(a)

0.9 x 10⁹ Nm² C²

(b)

9 x 10^-9 Nm²C²

(c)

9 x 10⁹ Nm^-2 C^-2

(d)

9 x 10⁹ Nm² C^-2

22.

A non-conducting charged ring carrying a charge of q, mass m and radius r is rotated about its axis with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is _____.

(a)

\(\\ \frac { q }{ m } \)

(b)

\(\\ \frac { 2q }{ m } \)

(c)

\(\\ \frac { q }{ 2m } \)

(d)

\(\\ \frac { q }{ 4m } \)

23.

In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 µF, then the voltage across L is

(a)

600 V

(b)

4000 V

(c)

400 V

(d)

1 V

24.

A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and the distance between the plates are each doubled then which is the quantity that will change?

(a)

Capacitance

(b)

Charge

(c)

Voltage

(d)

Energy density

25.

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of ______.

(a)

each of them increases

(b)

each of them decreases

(c)

copper increases and germanium decreases

(d)

copper decreases and germanium increases

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

Answers Key:

Multiple Choice Question

25 x 1 = 25

(d)
55 cm

(a)
smaller than

(b)
magnetron oscillator

(a)
amplitude

(b)
UV rays

(b)
three

(d)
hv

10.

(d)
gas-plasma

11.

(a)
-13.6

12.

13.

14.

r_n ∞ n²
r₁: r₂: r₃ = 1: 4: 9

15.

\(\lambda\propto \frac{1}{\sqrt{V}}\)
\(\frac{\lambda_1}{\lambda_2}=\frac{\sqrt{224\times10^3}}{\sqrt{14\times 10^3}}\)
\(=\sqrt{16}=4\)
\(\lambda_{\mathrm{2}}= \frac{\lambda_1}{4}\)

16.

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

17.

18.

(d)
π

19.

20.

(b)
\(\frac { {2 \varepsilon }_{ 0 }A }{ d } \\ \)

21.

(d)
9 x 10⁹ Nm² C^-2

22.

Magnetic moment,
μ = IA
Angular momentum,
L = Iω
Ratio \(\frac{p_m}{L}=\frac{(q/T)\pi r^2}{mr^2\omega}=\frac{q}{2m}\)

23.

\(\omega=250 \mathrm{rad} / \mathrm{s}, C=4 \times 10^{-} \mathrm{F} \)
\(R=100 \Omega, \quad \mathrm{V}_{\mathrm{R}}=40 \mathrm{~V} \)
\(\therefore I_{\mathrm{R}}=\frac{V_R}{100}=\frac{40}{100}=0.4 \mathrm{~A} \)
\(\omega=\frac{1}{\sqrt{L C}} \)
\(\omega^2=\frac{1}{L C} \)
\((250)^2=\frac{1}{L \times 4 \times 10^{-6}} \)
\(L=\frac{1}{4 \times(250)^2 \times 10^{-6}} \)
\(=\frac{1}{4 \times 250 \times 250 \times 10^{-6}} \)
\(=\frac{1}{1000 \times 10^{-6} \times 250} \)
\(=\frac{10^3}{250}=\frac{1000}{250}=4 \mathrm{H}\)
Voltage acnoss L, V_t= IX_L
V_L= l x L x ω
= 0.4 x 4 x 250
0.4 x 1000 = 400 V

24.

Energy density u_E \(=\frac{U}{volume}\)
If A' = 2A d ' = 2d
Then V ' = 2A x 2d = 4Ad = 4V
Then volume would be increased. So, energy density will change.

25.

Resistivity ∝ temperature for conductor. so, copper → decreases
Resistivity ∝\(\frac{1}{\text {temperature for semiconductor}}\)
so, germanium → increases.