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Physics M.C.Q (1 Marks)

MARCH 2024 · Gujarat Board (GSEB) STD 12 Science (GSEB - English Medium). 50 questions.

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M.C.Q (1 Marks)

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50 questions · auto-graded multiple-choice test.

MCQ 11 Mark
If a conducting wire of length $L$ is uniformly stretched to double its length, then its conductivity becomes ___________ .
  • A
    double
  • B
    4 times
  • C
    halved
  • ✓
    remain same
Answer
Correct option: D.
remain same
D
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MCQ 21 Mark
If a 12 pF capacitor is connected to a 50 V battery then the electrostatic energy stored in the capacitor is ___________.
  • A
    $1.5 \times 10^{-12} J$
  • B
    $1.5 \times 10^{-6} J$
  • ✓
    $1.5 \times 10^{-8} J$
  • D
    $3 \times 10^{-8} J$
Answer
Correct option: C.
$1.5 \times 10^{-8} J$
C
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MCQ 41 Mark
A charged capacitor is disconnected from the battery and if the distance between the two plates of the capacitor is increased then ___________ .
  • A
    Charge on plate will decrease
  • ✓
    Charge on plate will remain same
  • C
    The potential difference between the two plates will decrease
  • D
    Capacitance of the capacitor will increase
Answer
Correct option: B.
Charge on plate will remain same
B
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MCQ 51 Mark
By keeping a conductor in an external electric field and from the result obtained by electrostatics, which of the following options is wrong?
  • A
    Inside a conductor electrostatic field is zero
  • B
    At the surface of a charged conductor electric field must be perpendicular to the surface
  • ✓
    The interior of the conductor have excess charge in static situation
  • D
    Electrostatic potential is constant through out the volume of the conductor.
Answer
Correct option: C.
The interior of the conductor have excess charge in static situation
C
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MCQ 61 Mark
Charge $+Q$ is placed at the centre of a circular path of radius $r$. The work done to bring charge $+q$ from one end of the diameter to other end of the circular path in the electric field produced by charge + Q is ___________ .
  • A
    $\frac{k Q q}{r}$
  • B
    $\frac{k Q q}{2 r}$
  • ✓
    zero
  • D
    $\frac{2 k Q q}{r}$
Answer
Correct option: C.
zero
C
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MCQ 81 Mark
If two infinite plane sheets having same surface charge density $\sigma$ are placed parallel to each other, then the electric field between the two sheet is ___________ .
  • ✓
    zero
  • B
    $\frac{\sigma}{\varepsilon_0}$
  • C
    $\frac{\sigma}{2 \varepsilon_0}$
  • D
    $\frac{2 \sigma}{\varepsilon_0}$
Answer
Correct option: A.
zero
A
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MCQ 91 Mark
Three equal chares + q each are placed at the three vertices of an equilateral triangle. The electric field at the centroid of the triangle is ___________ .
  • A
    $\frac{3 k q}{r^2}$
  • B
    $\frac{k q}{r^2}$
  • ✓
    zero
  • D
    $\frac{\sqrt{3} k q}{2 r^2}$
Answer
Correct option: C.
zero
C
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MCQ 101 Mark
Two identical conducting spheres A and B having charges $+q$ and $-q$ are kept at ' d ' distance apart experience coulombian force $F$ between them. If $50 \%$ of charge is transferred from sphere B to A then the new coulombian force between them is ___________ .
  • A
    F
  • B
    $\frac{F}{2}$
  • ✓
    $\frac{ F }{4}$
  • D
    $\frac{2 F}{3}$
Answer
Correct option: C.
$\frac{ F }{4}$
C
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MCQ 111 Mark
The dimensional formula of electric field is ___________ .
  • ✓
    $\left[ M ^1 L^1 T^{-3} A^{-1}\right]$
  • B
    $\left[ M ^1 L^2 T^{-3} A^{-1}\right]$
  • C
    $\left[ M ^1 L^1 T^{-2} A^{-1}\right]$
  • D
    $\left[ M ^0 L^1 T^{-3} A^{-1}\right]$
Answer
Correct option: A.
$\left[ M ^1 L^1 T^{-3} A^{-1}\right]$
A
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MCQ 121 Mark
If an electric charge ' $q$ ' is placed at the centre of a cube, then the flux associated with each surface of the cube is ___________ .
  • A
    $\frac{q}{\varepsilon_0}$
  • ✓
    $\frac{q}{6 \varepsilon_0}$
  • C
    $\frac{q}{4 \varepsilon_0}$
  • D
    $\frac{q}{2 \varepsilon_0}$
Answer
Correct option: B.
$\frac{q}{6 \varepsilon_0}$
B
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MCQ 131 Mark
Image

If a diode having infinite reverse-bias resistance is connected in a circuit as shown in figure, then $I_1$ and $I_2$ are respectively ___________ .
  • ✓
    $0.0 A ; 0.2 A$
  • B
    $10.0 A: 0.0 A$
  • C
    $0.2 A: 0.0 A$
  • D
    $0.0 A: 0.0 A$
Answer
Correct option: A.
$0.0 A ; 0.2 A$
A
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MCQ 141 Mark
Which of the following substance have energy gap (Eg) more than 3 eV ?
  • A
    Metals
  • B
    Alloys
  • C
    Semiconductor
  • ✓
    Non-metals
Answer
Correct option: D.
Non-metals
D
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MCQ 151 Mark
What type of semiconductor is CdS?
  • A
    Elemental
  • B
    Organic
  • ✓
    Inorganic
  • D
    Organic polymer
Answer
Correct option: C.
Inorganic
C
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MCQ 161 Mark
When a forward bias is applied to a p-n juction it ___________ .
  • A
    raises the potential barrier
  • B
    reduces the majority carrier to zero
  • ✓
    lowers the potential barrier
  • D
    potential barrier remain same
Answer
Correct option: C.
lowers the potential barrier
C
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MCQ 171 Mark
In a p-type semiconductor, which of the following statements is true ?
  • A
    Electrons are majority charge carriers and trivalent atoms are the dopants
  • B
    Electrons are minority charge carriers and pentavalent atoms are the dopants
  • C
    Holes are minority carriers and pentavalent atoms are the dopants.
  • ✓
    Holes are majority carriers and trivalent atoms are the dopants
Answer
Correct option: D.
Holes are majority carriers and trivalent atoms are the dopants
D
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MCQ 181 Mark
The atomic masses of two isotopes of an element are 34.98 u and 36.98 u and their relative abundance are $75.4 \%$ and $24.6 \%$ respectively, then the average atomic mass of the element is ___________ .
  • A
    34.51 u
  • B
    36.46 u
  • ✓
    35.47 u
  • D
    35.99 u
Answer
Correct option: C.
35.47 u
C
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MCQ 191 Mark
According to Einsteins mass-energy equivalent relation, the energy equivalent of 1 mg of substance is ___________ (speed of light $c=3 \times 10^8 m / s$ )
  • A
    $9 \times 10^{13} J$
  • B
    $9 \times 10^{10} J$
  • ✓
    $9 \times 10^{-13} J$
  • D
    $9 \times 10^{-10} J$
Answer
Correct option: C.
$9 \times 10^{-13} J$
C
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MCQ 201 Mark
Which of the following element has maximum binding energy per nucleon?
  • A
    Uranium
  • B
    Lithium
  • C
    Tungsten
  • ✓
    Iron
Answer
Correct option: D.
Iron
D
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MCQ 211 Mark
The radius of nuclei of ${ }_{13}^{27} Al$ is ___________.\[\left(R_0=1.2 fm\right)\]
  • A
    $3.0 \times 10^{-15} m$
  • ✓
    $3.6 \times 10^{-15} m$
  • C
    $3.2 \times 10^{-14} m$
  • D
    $3.6 \times 10^{-12} m$
Answer
Correct option: B.
$3.6 \times 10^{-15} m$
B
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MCQ 221 Mark
Chossing the correct option complete the given nuclear fusion reaction that occurs in the sun :
\[{ }_2^3 H+{ }_2^3 H \rightarrow{ }_2^4 He+{ }_1^1 H+{ }_1^1 H+\] ___________ .
  • A
    0.42 MeV
  • B
    1.02 MeV
  • ✓
    12.86 MeV
  • D
    5.49 MeV
Answer
Correct option: C.
12.86 MeV
C
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MCQ 231 Mark
Kinetic energy of electron in one of the orbit hydrogen atom is $x$ then its total energy is ___________.
  • ✓
    $-x$
  • B
    $-\frac{x}{2}$
  • C
    $-2 x$
  • D
    $\frac{x}{8}$
Answer
Correct option: A.
$-x$
A
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MCQ 241 Mark
In accordance with the Bohr's model, the quantum number that characterises the earth's revolution around the sun in an orbit of radius $1.5 \times 10^{11} m$ with orbit speed $3 \times 10^4 m / s$ is ___________ . (Mass of earth is $6.0 \times 10^{24} kg, h=6.625 \times 10^{-34} Js$ )
  • A
    $2.6 \times 10^{72}$
  • ✓
    $2.6 \times 10^{74}$
  • C
    $2.6 \times 10^{39}$
  • D
    $2.6 \times 10^{73}$
Answer
Correct option: B.
$2.6 \times 10^{74}$
B
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MCQ 251 Mark
The size of atom in Thomson's model is ___________ the size in Rutherford's model.
  • A
    much greater then
  • ✓
    not different from
  • C
    much less than
  • D
    double
Answer
Correct option: B.
not different from
B
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MCQ 261 Mark
If the radius of hydrogen atom in its first orbit is $a_0$, then its radius in third excited state is.
  • A
    $3 a_0$
  • B
    $4 a_0$
  • C
    $9 a_0$
  • ✓
    $16 a_0$
Answer
Correct option: D.
$16 a_0$
D
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MCQ 271 Mark
The momentum of a photon of light of frequency $f$ is ___________ .
  • A
    $\frac{h c}{f}$
  • B
    $\frac{h}{c f}$
  • ✓
    $\frac{h f}{c}$
  • D
    $h c f$
Answer
Correct option: C.
$\frac{h f}{c}$
C
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MCQ 281 Mark
Threshold frequency of which of the following metal does not lie in the ultraviolet region. (In case of photoelectric effect)
  • A
    Zinc
  • B
    Cadmium
  • C
    Magnesium
  • ✓
    Sodium
Answer
Correct option: D.
Sodium
D
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MCQ 291 Mark
If de-Broglie wavelength of a dust particle of mass $1.0 \times 10^{-9} kg$ is $3 \times 10^{-25} m$ then the speed of the particle is ___________ . \[\left(h=6.625 \times 10^{-34} Js\right)\]
  • A
    $1.1 ms^{-1}$
  • B
    $1.0 kms ^{-1}$
  • C
    $1.2 kms ^{-1}$
  • ✓
    $2.2 ms^{-1}$
Answer
Correct option: D.
$2.2 ms^{-1}$
D
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MCQ 301 Mark
The photoelectric cut-off voltage in a certain experiment is 1.5 V . What is the maximum kinetic energy of photoelectrons emitted?
  • ✓
    1.5 Ev
  • B
    3.0 eV
  • C
    1.5 J
  • D
    $1.6 \times 10^{-19} J$
Answer
Correct option: A.
1.5 Ev
A
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MCQ 311 Mark
In the case of Photoelectric effect, on increasing the frequency of incident light, ___________ .
  • A
    Photoelectric current increases
  • B
    Photoelectric current decreases
  • ✓
    Stopping potential increases
  • D
    Stopping potential decreases
Answer
Correct option: C.
Stopping potential increases
C
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MCQ 321 Mark
Two waves having same intensity $I _0$ and originated from two non-coherent sources superpose at a point. The average intensity at that point is ___________ .
  • A
    $I _0$
  • ✓
    $2 I _0$
  • C
    $3 I _0$
  • D
    $4 I _0$
Answer
Correct option: B.
$2 I _0$
B
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MCQ 331 Mark
Which of the following figure is correct on the basis of Huygens principle for refraction of a plane wave by a thin prism?
  • A
    Image
  • ✓
    Image
  • C
    Image
  • D
    Image
Answer
Correct option: B.
Image
B
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MCQ 341 Mark
A small telescope has an objective lens of focal length 140 cm and eye piece of focal length 5 cm .The magnifying power of telescope for viewing distant object when the telescope is in normal adjustment is ___________ .
  • A
    145
  • B
    70
  • ✓
    28
  • D
    35
Answer
Correct option: C.
28
C
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MCQ 351 Mark
The speed of light in a medium of refractive index 1.25 is ___________ .
(Speed of light in vacuum is $3 \times 10^8 ms^{-1}$ )
  • ✓
    $2.4 \times 10^8 ms^{-1}$
  • B
    $2.0 \times 10^8 ms^{-1}$
  • C
    $1.5 \times 10^8 ms^{-1}$
  • D
    $1.25 \times 10^8 ms^{-1}$
Answer
Correct option: A.
$2.4 \times 10^8 ms^{-1}$
A
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MCQ 361 Mark
Which of the following waves is used in speed gun to measure the speed of ball in cricket match?
  • A
    Radio wave
  • ✓
    Micro wave
  • C
    Infrared waves
  • D
    Ultraviolet wave
Answer
Correct option: B.
Micro wave
B
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MCQ 371 Mark
Which of the following option represents Amperemaxwell Law ?
  • A
    $\int \overrightarrow{ B } \cdot \overrightarrow{d l}=\mu_0 i_c+\mu_0 \frac{d \phi_E}{d t}$
  • B
    $\oint \overrightarrow{ B } \cdot \overrightarrow{d l}=\mu_0 i_c+\varepsilon_0 \frac{d \phi_E}{d t}$
  • C
    $\oint \overrightarrow{ B } \cdot \overrightarrow{d l}=\mu_0 i_c+\frac{d \phi_E}{d t}$
  • ✓
    $\oint \overrightarrow{ B } \cdot \overrightarrow{d l}=\mu_0 i_c+\mu_0 \varepsilon_0 \frac{d \phi_E}{d t}$
Answer
Correct option: D.
$\oint \overrightarrow{ B } \cdot \overrightarrow{d l}=\mu_0 i_c+\mu_0 \varepsilon_0 \frac{d \phi_E}{d t}$
D
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MCQ 381 Mark
An L-C-R series circuit is connected to an AC source of peak voltage 240 V . The phase difference between voltage and current of this circuit is $45^{\circ}$ and resistance is $100 \Omega$, then the rms value of current through the circuit is ___________ .
  • A
    5.25 A
  • B
    1.7 A
  • C
    3.5 A
  • ✓
    1.2 A
Answer
Correct option: D.
1.2 A
D
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MCQ 391 Mark
From which of the following options the power factor of an A.C. circuit can be zero.
  • A
    R and L in series
  • B
    R and C in series
  • C
    L, C and R in series
  • ✓
    L and C in series
Answer
Correct option: D.
L and C in series
D
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MCQ 401 Mark
A 1.0 m long metallic rod is ratated with an angular frequency $200 rad / s$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field of 0.5 T parallel to the axis exist everywhere. The emf developed between the centre and the ring is ___________.
  • ✓
    100 V
  • B
    200 V
  • C
    50 V
  • D
    400 V
Answer
Correct option: A.
100 V
A
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MCQ 411 Mark
Mutual inductance of a system of two coil does not depend on ___________ .
  • A
    No, of turns of the coil
  • B
    Distance between two coil
  • C
    The relative permeability of the medium within the coil
  • ✓
    Current passing through the coils
Answer
Correct option: D.
Current passing through the coils
D
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MCQ 421 Mark
Current in a circuit falls from 5.0 A to 0.0 A in 0.1 s . If an average emf of 100 V induced then the value of self inductance of the circuit is ___________ .
  • A
    0.5 H
  • B
    1 H
  • ✓
    2 H
  • D
    4 H
Answer
Correct option: C.
2 H
C
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MCQ 431 Mark
The flux associated with a closed loop is $\phi_{(t)}=$ $3 t^2+2 t+5$ weber. If the resistance of the loop is $14 \Omega$, then the current induced in this coil in $t$ $=2 sec$ is ___________ .
  • ✓
    1 A
  • B
    2 A
  • C
    1.5 A
  • D
    2.5 A
Answer
Correct option: A.
1 A
A
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MCQ 441 Mark
A short bar magnet placed with its axis at $30^{\circ}$ with a uniform external magnetic field of $0,25 T$, experiences a torque of magnitude $4.5 \times 10^{-2} J$. The magnitude of the magnetic moment of the magnet will be ___________ $J ^{-1}$.
  • A
    0.18
  • ✓
    0.36
  • C
    0.54
  • D
    0.72
Answer
Correct option: B.
0.36
B
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MCQ 451 Mark
A conducting ring of radius R and one turn is formed from a conducting wire of length L and on passing current I the obtained magnetic dipole moment is $m$. If this wire is then converted to a ring of two turns and on passing electric current I, the new magnetic dipole moment obtained is _________.
  • ✓
    $\frac{m}{2}$
  • B
    2 m
  • C
    $\frac{m}{4}$
  • D
    4 m
Answer
Correct option: A.
$\frac{m}{2}$
A
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MCQ 461 Mark
A closely wound solenoid 120 cm long has 4 layers of windings of 400 turns each. The diameter of the solenoid is 1.8 cm . If current carried is 8.0 A, estimate the magnitude of $B$ inside the solenoid near its centre.
  • A
    $5.12 \pi \times 10^{-7} T$
  • B
    $5.12 \pi \times 10^{-3} T$
  • ✓
    $4.27 \pi \times 10^{-3} T$
  • D
    $8 \pi \times 10^{-3} T$
Answer
Correct option: C.
$4.27 \pi \times 10^{-3} T$
C
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MCQ 471 Mark
Which of the following graph represents magnetic field (B) versus distance $r$ from the centre of a long straight conducting wire of uniform cross sectional area carrying steady current I and radius $a$ ?
  • A
    Image
  • B
    Image
  • ✓
    Image
  • D
    Image
Answer
Correct option: C.
Image
C
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MCQ 481 Mark
If a battery of 12 V is connected across the diametrically end points A & B of a conducting ring of radius R and the current drawn from the battery is I , then the magnetic field produced at the centre of the ring due to the ring is ___________ .
  • ✓
    zero
  • B
    $\frac{\mu_0 I }{2 R }$
  • C
    $\frac{\mu_0 I}{4 \pi R}$
  • D
    $\frac{\mu_0 I}{R}$
Answer
Correct option: A.
zero
A
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MCQ 491 Mark
The storage battery of a car has an emf of 12 V . If the internal resistance of the battery is $0.6 \Omega$ then the maximum current that can be drawn from the battery is ___________ .
  • ✓
    20 A
  • B
    25 A
  • C
    30 A
  • D
    72 A
Answer
Correct option: A.
20 A
A
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MCQ 501 Mark
Resistivity of which of the following substance decrease on increasing the temperature?
  • A
    Copper
  • ✓
    Silicon
  • C
    Aluminium
  • D
    Nichrome
Answer
Correct option: B.
Silicon
B
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