TALHA’S PHYSICS ACADEMY

M.C.Qs Assessments for Board Exam 2022

Class : XII Max. Marks: 100

1. The average translational Kinetic energy per mole of molecules of a gas is:

*3/2 KT *2/3 KT *3/2 RT *2/3 RT

2. The area enclosed by P – V diagram of a Carnot cycle represents:

*energy loss due to leakage *useful work

*heat absorbed *Heat rejected

3. In an isothermal expansion, the Entropy of the system:

*Increases *Decreases *Becomes zero *Remains constant

4. Heat energy can’t be measure d in:

*Joule *B.T.U *Kelvin *Calorie

5. Absolute zero corresponds to this tempe rature on Fahrenheit scale:

*32 0 F *-180 0 F *-460 0 F *212 0 F

6. The average K.E. of the molecules of an ideal in a closed vessel is increased by a factor 4. What would
be pressure of the gas?

* It will remain the same * It will increases by a factor of 2

* It will increases by a factor of 4 * It will increases by a factor of √2

7. Real Gases obey Gas laws at

*Low pressure Low Temperature *High pressure High temperature

*Low pressure high Temperature *High Pressure Low temperature

8. Efficiency of Carnot Engine can’ t be expressed as:

∆𝑄 ∆𝑇 ∆𝑊 𝑄1 −𝑄2
*𝑄 * * *
1 𝑇1 𝑡 𝑄1

9. Boyle’s law holds good for an ideal gas in a process:

*Isothermal process *Isochoric process *Isobaric Process *All of these

10. In adiabatic expansion, inte rnal energy of gas:

*Increases * decreases *remains same *becomes zero

11. A particle of mass “m” and charge “q” is to be held motionless between two parallel and horizontal
charged plates. The electric field intensity between the plates will be:
𝑚𝑔 𝑞 𝑚𝑔 𝑞𝑣 𝑠𝑖𝑛𝜃
* 𝑞𝑣 *𝑚𝑔 * *
𝑞 𝑚

12. This is not a scalar quantity:

*Electromotive Force *Electric Flux *Electric Intensity *Electric Potential

13. If a dielectric, having ϵr = 2, inserted between the plates of a 20µF capacitor, its capacitance will:

*be halved *Remain the same *Be doubled *become zero

14. The number of electrons in one coulomb is:

*6.1 x 1020 *6.1 x 1018 *6.25 x 1018 *6.1 x 1019

15. If the area of plates of parallel plate capacitor is doubled, capacitance:

*remains unchanged *is half *is double *is increased for times

16. Two Capacitors of 3µF and 6µF are connected in series, their equivalent capacitance is

*9 µF *2 µF *0.5 µF *0.25 µF
∆𝑽
17. The relation is called
∆𝒓

*Gauss’ Law *Electric flux *Electric Intensity *Potential Difference

18. The electric potential is zero at

*Inside a conductor *Midway between Opposite Charges

*Midway between same charges *None of these

19. Decreasing the separation of two positive charges by half will cause electrostatic force of repulsion to
change by

*4 times *3 times *0.5 times *0.25 times

20. 1 MeV is equal to:

* 1.6 x 10-19 J * 1.6 x 10-13 J *1.6 x 1018 J * 1.6 x 1019 J

21. Resistance of a curre nt carrying wire does not depend on the:

*Temperature *Length *Area *Electric Current

22. Resistance of 10 ohm, 30 ohm and 40 ohm are connected in the series. If current in 10 ohm resistance
is 0.1 A then the current through 40 ohm resistor will be:

*0.4 A *0.3 A *0.1 A *0.08 A

23. A metallic wire of length L, resistance R and resistivity 𝝆 is cut into two equal parts. The resistivity of
each part would be:
𝜌 𝜌
*𝜌 * 2𝜌 * *
2 4

24. Two wires of resistance R 1 and R 2 are connected in a series in a circuit. If R 1 is greater than R 2 , the
heating would be:

*more in R1 *more in R2 *same in R1 and R2 *all of these

25. The comme rcial unit of electrical energy is:

*ohm *watt *kilo watt hour *ampere

26. Powe r dissipated in two parallel resistors is inversely proportional to their:

*Potential difference * Capacitance * Current * Resistances

27. A resistor carries a current I. The power dissipated is P. the power dissipated if the same resistor
carries the current 3 I is:
*9P * P/3 * 3P *P

28. With the increase of temperature, the resistance of a semi conductor

* increase * decrease * remains constant * becomes zero

29. Drift velocity of electrons is due to

* motion of conduction electrons due to random collisions.
* motion of conduction electrons due to electric field E
* repulsion to the conduction electrons due to inner electrons of ions.
* collision of conduction electrons with each other.

30. Loss of Voltage in Electrical circuits is given by:

*IR * Ir * IR + Ir (d) IR – Ir

31. Non inductive coil in a resistance box is used to minimize:

*eddy current *heat loss *mutual inductance *self inductance

32. The practical application of phenomenon of mutual induction is:

*AC Generator *Transformer *Rectifier *Dynamo

33. When an A.C. generator is conve rted into D.C generator slip ring is replaced by:

*a dynamo *a split ring *a field coil *an inductor

34. The path of a neutron, moving perpendicularly through a magnetic field, is:

*Straight line *Circular *Oval *Sinusoidal

35. The motional e mf induced in a coil is independent of:

*change of flux *number of turns *time *resistance

36. This force is experienced by a current carrying conductor placed in uniform magnetic field
*F = I ( L × B ) *F = I ( v × B ) *F = I ( E × B ) *F = I ( B × L )

37. Tesla (T) is equal to

*newton ×coulomb *newton × ampere

*newton / (ampere × meter) *(newton ×meter)/ampere

38. What is the function of a transformer?

* Transformer is used to step down or up the AC voltages and currents

* Transformer is used to step down or up the DC voltages and currents

* Transformer converts DC to AC voltages

* Transformer converts AC to DC voltages

39. A 500 turns solenoid develops an average induced voltage of 60 V. Over what time inte rval must a
flux change of 0.06 Wb occur to produce such a voltage?

* 0.01 s * 0.1 s * 0.5 s *5s

40. Two free parallel wires carrying current in opposite direction:

* do not affect each other * attract each other

* repel each other * none of these

41. Concave magnetic poles, with a fixed soft iron cylinder in moving coil galvanometer, make the
magnetic field:

*weak *radial *zero *infinite

42. A device consisting of ammete r, voltmeter and ohmmeter is called:

*Potentiometer *Multimeter *CRO *VTVM

43. An instrume nt which can measure and compare potentials without drawing any current from the
circuit is known as a/an:

*Ammeter *Voltmeter *Potentiometer *AVO-meter

44. If length of wire of potentiometer is increased, the accuracy in the determination of null point:
*increases *decreases *remain the same *becomes zero

45. This is a high resistance instrument:

*Voltmeter *Ammeter *Galvanometer *Motor

46. To measure the potential of a circuit a voltmeter is connected:

*always in series *always in parallel *diagonal *perpendicular

47. Sensitivity of Galvanometer is given by

* CBNA *1/CBNA * C/BNA * BAN/C

48. The couple per unit twist of the suspension is equal to

* Sum of deflection and restoring torque *Product of deflection and restoring torque

* Deflection per restoring torque *Restoring torque per deflection

49. The function of shunt in an amme ter is to

*By pass the current *Increase the sensitivity of the ammeter

*Increase the resistance of ammeter *None of these

50. The inte rnal resistance of a voltmeter must be very high so that

*Minimum current passes through the meter *Range is high

*Accuracy is high *Loading effect is maximum

51. The application of electric potential across the diode is called:

*doping *biasing *impurity addition *potential barrier

52. Emitter base junction is forward biased in:

*Neither PNP and NPN transistor *NPN transistor

*PNP transistor *Both PNP and NPN transistor

53.In a semiconductor, the energy gap between the valance band and the conduction band is:

*Narrow *wide *Not present *infinity

54. These are Donor impurities:

*Li and G *Ga and Si *Sb and As *In and Ga

55. Hole in a semiconductor is actually the:

*Electron *Positron
*Helium nucleus *vacancy in the valance band

56. The speed of electromagnetic wave is given by:

1 1
* * * 𝜖0 𝜇0 *𝜖0 𝜇0
𝜖0𝜇0 𝜖0𝜇0

57. With increase in temperature the resistance of semi conductor:

*increase *decrease *remains constant *becomes zero

58. Pn junction diode works as an insulator if connected:

*to AC source *in forward bias *in reverse bias *all of these

59. Amplitude Modulation in a signal means:

* Change in the time period of signal * Change in the vertical width of a signal

*Change in the horizontal width of signal *All of them

60. Which of the following is not a semi-conductor

*Germanium *Silicon *Copper *Gallium

61. Stefan Boltzmann’s law is:

*E = σT *E = σT2 *E = σT3 *E = σT4

62. If m0 is the rest mass of an electron, Pair production takes place only if the minimum ene rgy of
incident photon is equal to:
2𝑚 0 2
* *𝑚 *𝑚 0 𝑐 2 *2𝑚 0 𝑐 2
𝑐2 0𝑐
2

63. In the phenome non of photoelectric effect, it the frequency of incident radiation is increased, the
require d stopping potential:

*Increases *decreases *does not change *Become zero

64. In Compton’s scattering expe riment, the scattered photon has a:

*frequency less than that of incident photon *Frequency greater than that of incident photon

*same frequency as that of incident photo *wavelength shorter than that of incident photon

65. As the temperature of the black body is raised, the wavelength corresponding to the maximum
intensity shifts towards:

*similar wavelength *shorter wavelength *longer wavelength *none of these

66. The photoelectric emission takes place if:

*h v < Øo * h v > Øo * h vo > Ø *V < Øo
67. The diode which gives visible light whe n energized is called:

*LCD * Photo diode * LED * photo voltaic cell

68. A set of coordinate axes with respect to which measurements are made is called:

* frame of reference * inertial frame of reference

*non- inertial frame of reference * none of these

69. If the sun radiates energy at the rate of 4 x 1026 Js-1, what is the rate at which its mass is decreasing?

* 5.54 x 109 kgs-1 * 4.44 x 109 kgs-1 * 3.44 x 109 kgs-1 * 2.44 x 109 kgs-1

70. If an object reaches the speed of light, it’s length changes to

* Infinite * Double of the value * Half of the value * Zero

71. The principle of laser production is:

*Stimulated emission *Stimulated emission

*Stimulated absorption *Spontaneous emission

72. The ratio of the radius of 3rd orbit in hydrogen atom to the radius of 1 st bohr orbit is:

*12:1 *3:1 *6:1 *9:1

73. In Laser, the lifetime of an electron in metastable state is of the order of:

*10-8 s *10-5 s *10-3 s *10-1 s

74. Balme r series of Hydrogen atom s pectrum lies in the:

*Radio wave region *Infra red region *visible region*ultraviolet region

75. Laser produces:

*A electron beam *A neutron beam

*A coherent beam of light *none of these

76. The wavelength of x ray is in the region:

*0.01 nm to 0.1 nm *1 A to 100 A

*0.1 A to 1 m *0.1 nm to 1.0 nm

77. In a hydrogen atom Balmer series electron falls into:

* n= 1 * n= 2 * n= 3 *n = 4

78. According to the Bohr’s theory, angular mome ntum of electron is integral multiple of:
ℎ 2𝜋 1
* *ℎ * *
2𝜋 ℎ ℎ

79. The Condition in which more electrons are present in higher energy then lowe r energy level is called:

* Normal Population *Population Inversion * Amplification *Optical Pumping

80. Ruby crystal is formed whe n Al ion is replaced by

*Helium ion *Hydrogen ion * Sodium ion * Chromium ion

81. The binding energy of deuteron (1 H2 ) is 23 Mev, its binding ene rgy pe r nucleon will be:

*11.5 MeV *0.2 MeV *1 MeV *0.51 MeV

82. In the process of positive beta emission, charge numbe r of daughter nucleus:

*is increased *is decreased *remains the same *is doubled

83. The half life of radium is 1600 years. After 6400 years, the sample of surviving radium will be its:

*1/4th *1/8th *1/ 16 th *half

84. After alpha decay, the nucleus has its:

*charge number decreased by four *charge number increased by four

* mass number decreased by four * mass number increased by four

85. High energy neutron may be absorbed by 3 Li6 to produce:

*One alpha particle *two alpha particles

*one alpha and one beta particles *One beta and one gamma particles

86. LMFBR is the abbreviation of:

*Liquid metal fast breeder reactor *Lithium metal of Fission and Bomb Radiation

* Lithium metal Fission breeder reactor *None of these

87. Packing Fraction is the:

* Binding energy Per mass defect *Mass defect Per binding energy

*Mass defect Per nucleon *Binding energy Per nucleon

88. How many isotopes does Hydrogen has?

* One isotope *two isotopes * three isotopes * four isotopes

89. Number of Neutrons in 92 U235 is:

*152 *148 *143 *92

90. As time passes, the rate of decay of a radioactive element:

*decrease *remains constant *Increase * Becomes infinity

91. The method of finding the age of specimen by C14 is called:

*artificial radioactivity *Radio carbon dating *half life *radiography

92. The rate of flow of blood in the human body can be traced by using this radio isotope:

*20Ca48 *6 C12 *1 H3 *11Na24

93. If radioactive Calcium, 20 Ca45 is taken by man or animal, this percentage of it deposits in the bones of
young one:

*20 *60 *90 *100

94. This device is used to make the path of ionizing particles visible:

*Geiger Muller counter *Wilson cloud chamber

*Van Dee Graff Generator *Cyclotron

151
95. A small quantity of radioactive Iodine 53 I is taken in food, most of it is deposited in the:

*Thyroid glands *Bones *Brain *Stomach

96. This is highly ionizing particle:

*α *β *γ *Proton

97. In treating localized cancerous tumor, a narrow beam of this is used:

*α – Rays from Cobalt – 60 *β – rays from Cobalt – 60

*γ – rays from Cobalt – 60 *Laser form Cobalt – 60

98. Leukemia is also called

*Skin cancer *Blood cancer *Carcinomas * Sarcoma

99. Radiation sickness is damage to your body caused by a large dose of radiation often received over a
short pe riod of time (acute).

*Radiation sickness * Blood cancer * Carcinomas * Sarcoma

100. Very high penetrating powe r is falling on earth from outer space are called.

*cosmic rays *Neutrinos * γ rays * sun rays