Class 12 Physics Ch-3 Electrostatics & Current Electricity MCQs Exam 2027

Unit 1 & 2: Electrostatics & Current Electricity

1. A cell of internal resistance ‘$r$‘ is connected to an external resistance ‘$R$‘. Current in $R$ will be maximum if: [BSEB 2026]

(A) $R = r/2$

(B) $R = r$

(C) $R > r$

(D) $R < r$

2. In a metallic conductor, the flow of current is due to: [BSEB 2026]

(A) Free electrons

(B) Protons

(C) Both free electrons and protons

(D) Bound electrons

3. Which of the following does not affect the resistance of a conducting wire? [BSEB 2026]

(A) Length

(B) Temperature

(C) Material

(D) Applied potential difference

4. Ohm’s law is not applicable when: [BSEB 2026]

(A) Temperature changes

(B) Temperature remains constant

(C) Potential difference changes

(D) None of these

5. Which of the following expressions represents electrical energy? [BSEB 2026]

(A) $V \cdot I \cdot t$

(B) $V \cdot I$

(C) $I \cdot R^2 \cdot t$

(D) $V^2/R$

6. The relationship between current density ($\vec{J}$), specific conductivity ($\sigma$), and electric field ($\vec{E}$) is: [BSEB 2026]

(A) $\vec{E} = \sigma \vec{J}$

(B) $\vec{E} = \sigma / \vec{J}$

(C) $\vec{J} = \vec{E} / \sigma$

(D) $\vec{J} = \sigma \vec{E}$

7. The value of the yellow color code in a carbon resistor is: [BSEB 2026]

(A) 4

(B) 2

(C) 3

(D) 5

8. In a parallel combination of resistors, the equivalent resistance: [BSEB 2026]

(A) Decreases

(B) Increases

(C) Remains the same

(D) None of these

9. The S.I. unit of electric flux is: [BSEB 2021]

(A) Ohm-meter

(B) Ampere-meter

(C) Volt-meter

(D) (Volt-meter)$^{-1}$

10. Relation between drift velocity ($v_d$) and applied electric field ($E$) is: [BSEB 2018]

(A) $v_d \propto \sqrt{E}$

(B) $v_d \propto E$

(C) $v_d \propto E^2$

(D) $v_d = \text{constant}$

11. Kilowatt-hour (kWh) is the unit of: [BSEB 2015]

(A) Power

(B) Energy

(C) Torque

(D) Force

12. Kirchhoff’s First Law ($\sum I = 0$) is based on the principle of conservation of: [BSEB 2024]

(A) Energy

(B) Charge

(C) Momentum

(D) Mass

13. Resistance of an ideal ammeter is: [BSEB 2022]

(A) Zero

(B) Very small

(C) Very large

(D) Infinite

14. The element used in an electric heater is: [BSEB 2017]

(A) Copper

(B) Platinum

(C) Tungsten

(D) Nichrome

15. Wheatstone Bridge is used to measure: [BSEB 2017]

(A) Only high resistance

(B) Only low resistance

(C) Both high and low resistance

(D) Potential difference

16. Electron-volt (eV) is the measure of: [BSEB 2020]

(A) Charge

(B) Potential difference

(C) Current

(D) Energy

17. Specific resistance of a conductor depends on its: [BSEB 2023]

(A) Length

(B) Area of cross-section

(C) Mass

(D) Nature of material

18. The S.I. unit of potential gradient is: [BSEB 2021]

(A) Vm

(B) V/m

(C) V/$m^2$

(D) $\Omega \cdot m$

19. Dimensional formula of electromotive force (e.m.f) is: [BSEB 2016]

(A) $[ML^2T^{-2}]$

(B) $[ML^2T^{-3}A^{-1}]$

(C) $[MLT^{-2}]$

(D) $[ML^2T^{-3}]$

20. 1 Ampere is equal to: [BSEB 2021]

(A) 1 Coulomb / 1 Second

(B) 1 Coulomb $\times$ 1 Second

(C) 1 Volt $\times$ 1 Ohm

(D) 1 Ohm / 1 Volt

21. Ampere-hour is the unit of: [BSEB 2022]

(A) Power

(B) Charge

(C) Energy

(D) Potential difference

22. If the length of a wire is doubled by stretching, its new resistance becomes: [BSEB 2019]

(A) $2R$

(B) $4R$

(C) $R/2$

(D) $R/4$

23. The algebraic sum of all currents meeting at a point in an electrical circuit is: [BSEB 2016]

(A) Zero

(B) Infinite

(C) Positive

(D) Negative

24. The resistance of a healthy human body is: [BSEB 2011]

(A) 50,000 $\Omega$

(B) 10,000 $\Omega$

(C) 1,000 $\Omega$

(D) 10 $\Omega$

25. Potentiometer is used to measure: [BSEB 2021]

(A) Current

(B) Resistance

(C) e.m.f. of a cell

(D) None of these

26. When an ammeter is shunted, its total resistance: [BSEB 2023]

(A) Increases

(B) Decreases

(C) Remains constant

(D) None of these

27. Heat produced in a conductor of resistance $R$ due to current $I$ for time $t$ is: [BSEB 2021]

(A) $I \cdot R \cdot t$

(B) $I \cdot R^2 \cdot t$

(C) $I^2 \cdot R \cdot t$

(D) $V \cdot I^2 \cdot t$

28. Which of the following is the best conductor of electricity? [BSEB 2021]

(A) Silver

(B) Copper

(C) Gold

(D) Zinc

29. The power of an electric circuit is: [BSEB 2015]

(A) $V \cdot R$

(B) $V^2 \cdot R$

(C) $V^2 / R$

(D) $V^2 \cdot R \cdot I$

30. The resistivity of a conductor increases with: [BSEB 2018]

(A) Increase in temperature

(B) Increase in cross-section area

(C) Decrease in length

(D) Decrease in temperature

31. Three resistors of $1 \Omega$ each are connected in series. The equivalent resistance is: [BSEB 2018]

(A) $1/3 \Omega$

(B) $3 \Omega$

(C) $1 \Omega$

(D) Zero

32. Absorbed electrical energy is: [BSEB 2017]

(A) Inversely proportional to potential difference

(B) Proportional to potential difference

(C) Proportional to the square of potential difference

(D) None of these

Unit 3: Magnetic Effects of Current & Magnetism

33. A particle of mass $m$ and charge $q$ enters a magnetic field $B$ at an angle $\theta$. The radius of the path is: [BSEB 2026]

(A) $mv/qB$

(B) $mv \cos \theta / qB$

(C) $mv \sin \theta / qB$

(D) $2\pi mv/qB$

34. Magnetic dipole moment of a circular loop of radius $R$ carrying current $I$ is: [BSEB 2026]

(A) $IR^2$

(B) $IR$

(C) $2\pi IR$

(D) $\pi IR^2$

35. Inside a current-carrying solenoid, magnetic field lines are: [BSEB 2026]

(A) Circular

(B) Divergent

(C) Parabolic

(D) Parallel and straight

36. Relative permeability ($\mu_r$) is equal to: [BSEB 2026]

(A) $\mu / \mu_0$

(B) $\mu_0 / \mu$

(C) $\mu \cdot \mu_0$

(D) $\mu – \mu_0$

37. The dimensions of $B^2/2\mu_0$ are same as that of: [BSEB 2026]

(A) Energy density

(B) Work

(C) Momentum

(D) Power

38. Force acting on a charge $q$ moving in a magnetic field $\vec{B}$ with velocity $\vec{v}$ is: [BSEB 2026]

(A) $q(\vec{v} \times \vec{B})$

(B) $(\vec{v} \times \vec{B})/q$

(C) $q/(\vec{v} \times \vec{B})$

(D) None of these

39. On moving from the North Pole to the Equator, the value of the angle of dip: [BSEB 2026]

(A) Increases

(B) Decreases

(C) Remains constant

(D) First increases then decreases

40. Magnetic moment of a magnet is a: [BSEB 2026]

(A) Scalar quantity

(B) Vector quantity

(C) Neutral quantity

(D) None of these

41. The S.I. unit of magnetic flux is: [BSEB 2022]

(A) Weber

(B) Tesla

(C) Henry

(D) Joule

42. The value of the angle of dip at the Earth’s magnetic poles is: [BSEB 2019]

(A) $0^\circ$

(B) $45^\circ$

(C) $90^\circ$

(D) $180^\circ$

43. Nickel is: [BSEB 2020]

(A) Diamagnetic

(B) Paramagnetic

(C) Ferromagnetic

(D) None of these

44. To convert a galvanometer into an ammeter, one needs to connect: [BSEB 2022]

(A) Low resistance in parallel

(B) High resistance in parallel

(C) Low resistance in series

(D) High resistance in series

45. The expression for Lorentz force is: [BSEB 2018]

(A) $\vec{F} = q(\vec{E} + \vec{v} \times \vec{B})$

(B) $\vec{F} = q(\vec{E} – \vec{v} \times \vec{B})$

(C) $\vec{F} = q(\vec{v} + \vec{E} \times \vec{B})$

(D) $\vec{F} = q(\vec{B} + \vec{v} \times \vec{E})$

46. Relation between geometric length ($L_g$) and magnetic length ($L_m$) of a magnet is: [BSEB 2021]

(A) $L_m = \frac{5}{6} L_g$

(B) $L_m = \frac{6}{5} L_g$

(C) $L_m = L_g$

(D) $L_m = 2 L_g$

47. A sensitive galvanometer can be converted into a voltmeter by connecting: [BSEB 2015]

(A) Low resistance in parallel

(B) High resistance in parallel

(C) Low resistance in series

(D) High resistance in series

Unit 4 & 5: Electromagnetic Induction, AC & EM Waves

48. An example of natural electromagnetic induction is: [BSEB 2026]

(A) Radio

(B) Television

(C) Battery charging

(D) Lightning

49. The S.I. unit of self-inductance is: [BSEB 2021]

(A) Coulomb

(B) Volt

(C) Ohm

(D) Henry

50. A device that converts mechanical energy into electrical energy is called: [BSEB 2025]

(A) Solar cell

(B) Dynamo

(C) Electric motor

(D) Transformer

51. Hot wire ammeter measures the ______ value of AC: [BSEB 2023]

(A) Peak

(B) Average

(C) RMS (Root Mean Square)

(D) None of these

52. In a step-down transformer, which quantity decreases? [BSEB 2020]

(A) Current

(B) Voltage

(C) Power

(D) Frequency

53. Lenz’s law is a consequence of the law of conservation of: [BSEB 2015]

(A) Charge

(B) Mass

(C) Energy

(D) Momentum

54. Inductive reactance ($X_L$) is given by: [BSEB 2021]

(A) $2\pi f L$

(B) $1 / (2\pi f L)$

(C) $2\pi f / L$

(D) $2\pi L / f$

55. For TV broadcasting, the frequency range used is: [BSEB 2021]

(A) 30–300 Hz

(B) 30–300 kHz

(C) 30–300 MHz

(D) 30–300 GHz

56. Nature of electromagnetic waves is: [BSEB 2017]

(A) Transverse

(B) Longitudinal

(C) Both (A) and (B)

(D) None of these

57. Velocity of light in vacuum ($c$) is related to $\mu_0$ and $\epsilon_0$ as: [BSEB 2023]

(A) $c = 1 / \sqrt{\mu_0 \epsilon_0}$

(B) $c = \sqrt{\mu_0 \epsilon_0}$

(C) $c = \mu_0 \epsilon_0$

(D) $c^2 = \mu_0 / \epsilon_0$

Unit 6: Optics

58. Which of the following has the highest refractive index? [BSEB 2021]

(A) Glass

(B) Water

(C) Iron

(D) Diamond

59. The cause of the color of light is its: [BSEB 2024]

(A) Frequency

(B) Velocity

(C) Phase

(D) Amplitude

60. The final image in an astronomical telescope is: [BSEB 2024]

(A) Real and erect

(B) Real and inverted

(C) Virtual and inverted

(D) Virtual and erect

61. Cylindrical lenses are used to correct the eye defect called: [BSEB 2020]

(A) Myopia

(B) Hypermetropia

(C) Astigmatism

(D) Presbyopia

62. The length of an astronomical telescope for normal adjustment is: [BSEB 2023]

(A) $f_o – f_e$

(B) $f_o \times f_e$

(C) $f_o / f_e$

(D) $f_o + f_e$

63. Which phenomenon confirms the transverse nature of light? [BSEB 2017]

(A) Interference

(B) Reflection

(C) Polarization

(D) Refraction

64. Optical path is equal to: [BSEB 2022]

(A) Refractive index $\times$ path length

(B) Refractive index / path length

(C) Path length / refractive index

(D) Refractive index + path length

65. The image formed by a simple microscope is: [BSEB 2019]

(A) Virtual and erect

(B) Virtual and inverted

(C) Real and erect

(D) Real and inverted

66. Convex lens is used to correct: [BSEB 2021]

(A) Near-sightedness

(B) Far-sightedness (Hypermetropia)

(C) Presbyopia

(D) Astigmatism

67. Blue color of the sky is due to: [BSEB 2022]

(A) Scattering

(B) Diffraction

(C) Interference

(D) Polarization

68. Mirage is caused by: [BSEB 2020]

(A) Total Internal Reflection

(B) Refraction only

(C) Diffraction

(D) Interference

69. Power of a lens is measured in: [BSEB 2016]

(A) Watt

(B) Candela

(C) Dioptre

(D) Lumen

Unit 7, 8 & 9: Modern Physics & Communication

70. The dimensions of Planck’s constant are: [BSEB 2024]

(A) $[ML^2 T^{-1}]$

(B) $[ML^2 T^{-2}]$

(C) $[ML T^{-1}]$

(D) $[ML T^{-2}]$

71. Rest mass of a photon is: [BSEB 2023]

(A) Zero

(B) Infinite

(C) $9.1 \times 10^{-31}$ kg

(D) $1.6 \times 10^{-27}$ kg

72. Which series of the hydrogen spectrum lies in the ultraviolet region? [BSEB 2025]

(A) Lyman series

(B) Balmer series

(C) Paschen series

(D) Bracket series

73. The expression for radioactive decay is: [BSEB 2021]

(A) $N = N_0 e^{-\lambda t}$

(B) $N = N_0 e^{\lambda t}$

(C) $N = N_0 (1 – e^{-\lambda t})$

(D) $\lambda = N_0 e^{-Nt}$

74. The source of solar energy is: [BSEB 2022]

(A) Nuclear fission

(B) Nuclear fusion

(C) Chemical reaction

(D) None of these

75. The Boolean expression for ‘OR’ gate is: [BSEB 2021]

(A) $A \cdot B = Y$

(B) $A + B = Y$

(C) $\bar{A} = A$

(D) $A \cdot B = 0$

76. The Boolean expression for ‘NAND’ gate is: [BSEB 2024]

(A) $A \cdot B = Y$

(B) $A + B = Y$

(C) $\overline{A \cdot B} = Y$

(D) $\overline{A + B} = Y$

77. The width of the forbidden energy gap in semiconductors is approximately: [BSEB 2025]

(A) 1 eV

(B) 6 eV

(C) 10 eV

(D) 15 eV

78. Majority charge carriers in p-type semiconductors are: [BSEB 2020]

(A) Electrons

(B) Holes

(C) Photons

(D) Protons

79. Majority charge carriers in n-type semiconductors are: [BSEB 2021]

(A) Electrons

(B) Holes

(C) Protons

(D) Neutrons

80. Alpha ($\alpha$) particle is: [BSEB 2019]

(A) Electron

(B) Proton

(C) Helium nucleus

(D) Hydrogen nucleus

81. The decimal number 15 in binary is: [BSEB 2020]

(A) $(1010)_2$

(B) $(1100)_2$

(C) $(1111)_2$

(D) $(1101)_2$

82. Cathode rays are: [BSEB 2018]

(A) Stream of electrons

(B) Stream of protons

(C) Stream of neutrons

(D) Stream of photons

83. The time during which the amount of a radioactive substance becomes half of its initial amount is: [BSEB 2022]

(A) Average life

(B) Half-life

(C) Decay constant

(D) Time period

84. A diode is used as a: [BSEB 2019]

(A) Amplifier

(B) Oscillator

(C) Modulator

(D) Rectifier

85. Modulation index of amplitude modulation lies between: [BSEB 2021]

(A) 0 and $\infty$

(B) 1 and 10

(C) 0 and 1

(D) 0.5 and 1.5

86. Frequency of matter waves is given by: [BSEB 2025]

(A) $E/h$

(B) $h/E$

(C) $E \cdot h$

(D) $E^2/h$

87. Which rays are similar to X-rays? [BSEB 2017]

(A) Alpha rays

(B) Beta rays

(C) Gamma rays

(D) Cathode rays

88. 1 atomic mass unit (amu) is equal to: [BSEB 2024]

(A) $1.6 \times 10^{-27}$ kg

(B) $1.6 \times 10^{-31}$ kg

(C) $1.6 \times 10^{-19}$ kg

(D) $9 \times 10^9$ kg

89. The energy of an electron in the first orbit of Hydrogen is $-13.6$ eV. Energy in the second orbit is: [BSEB 2021]

(A) $-3.4$ eV

(B) $-6.8$ eV

(C) $-27.2$ eV

(D) $-1.5$ eV

90. Optical fiber works on the principle of: [BSEB 2022]

(A) Scattering

(B) Refraction

(C) Total Internal Reflection

(D) Interference

91. The unit of intensity of electric field is: [BSEB 2025]

(A) $C/N$

(B) $N/C$

(C) $V/C$

(D) $N \cdot C$

92. Value of $1/4\pi \epsilon_0$ is: [BSEB 2021]

(A) $9 \times 10^9$ N$m^2 C^{-2}$

(B) $9 \times 10^{-9}$ N$m^2 C^{-2}$

(C) $9 \times 10^{12}$ N$m^2 C^{-2}$

(D) $9 \times 10^{-12}$ N$m^2 C^{-2}$

93. The surface charge density ($\sigma$) is: [BSEB 2022]

(A) Charge $\times$ Area

(B) Charge / Area

(C) Charge / Volume

(D) Charge $\times$ Volume

94. Capacitance of a parallel plate capacitor is: [BSEB 2021]

(A) $\epsilon_0 A / d$

(B) $\epsilon_0 d / A$

(C) $A d / \epsilon_0$

(D) $\epsilon_0 A d$

95. Dielectric constant for water is: [BSEB 2020]

(A) 80

(B) 60

(C) 1

(D) 42.5

96. 1 Farad is equal to: [BSEB 2022]

(A) 1 $C V^{-1}$

(B) 1 $C V^{-2}$

(C) 1 $C^2 V$

(D) 1 $C V$

97. Work done in rotating a dipole in an electric field $E$ is: [BSEB 2021]

(A) $W = pE(1 – \cos \theta)$

(B) $W = pE \tan \theta$

(C) $W = pE \sin \theta$

(D) None of these

98. The potential energy of an electric dipole is minimum when the angle between dipole moment and electric field is: [BSEB 2025]

(A) $0$

(B) $\pi/2$

(C) $\pi$

(D) $3\pi/2$

99. If $n$ capacitors of equal capacitance $C$ are connected in series, the equivalent capacitance is: [BSEB 2024]

(A) $n C$

(B) $C / n$

(C) $n^2 C$

(D) $C / n^2$

100. Power factor of $L-R$ circuit is: [BSEB 2019]

(A) $R / \sqrt{R^2 + \omega^2 L^2}$

(B) $R + \omega L$

(C) $\sqrt{R^2 + \omega^2 L^2} / R$

(D) $\omega L / R$

101. Unit of reactive power is: [BSEB 2025]

(A) Watt

(B) VA

(C) VAR

(D) Ohm

102. Choke coil is used to control: [BSEB 2021]

(A) AC current

(B) DC current

(C) Both AC and DC

(D) None of these

103. The ratio of peak value and RMS value of AC is: [BSEB 2022]

(A) $1/\sqrt{2}$

(B) $\sqrt{2}$

(C) $2$

(D) $1/2$

104. Which EM wave has the shortest wavelength? [BSEB 2023]

(A) X-rays

(B) Gamma rays

(C) Ultraviolet rays

(D) Microwaves

105. Brewster’s Law is: [BSEB 2021]

(A) $\mu = \sin i_p$

(B) $\mu = \tan i_p$

(C) $\mu = \cos i_p$

(D) $\mu = \cot i_p$

106. Fringe width ($\beta$) in interference is: [BSEB 2022]

(A) $D \lambda / d$

(B) $d \lambda / D$

(C) $D d / \lambda$

(D) $\lambda / D d$

107. Light travels in a straight line because: [BSEB 2024]

(A) Its velocity is very high

(B) Its wavelength is very small

(C) It is not affected by atmosphere

(D) None of these

108. Resolving power of a human eye (in minutes) is: [BSEB 2021]

(A) 1

(B) 60

(C) 2

(D) 1/2

109. Focal length of a plane mirror is: [BSEB 2011]

(A) Infinity

(B) Zero

(C) 25 cm

(D) $-25$ cm

110. Magnifying power of a magnifying glass of power 12D is: [BSEB 2022]

(A) 4

(B) 12

(C) 3

(D) 25

111. The phenomenon of bending of light at the corners of an obstacle is: [BSEB 2021]

(A) Refraction

(B) Reflection

(C) Diffraction

(D) Interference

112. Primary rainbow is formed due to: [BSEB 2025]

(A) Two refractions and one total internal reflection

(B) Two refractions and two total internal reflections

(C) One refraction and one reflection

(D) None of these

113. Work function of photoelectric effect depends on: [BSEB 2024]

(A) Nature of the metal

(B) Frequency of light

(C) Intensity of light

(D) None of these

114. Mass-energy equivalence relation is: [BSEB 2021]

(A) $E = m/c^2$

(B) $E = mc^2$

(C) $E = \sqrt{m} c$

(D) $E = m^2 c$

115. Half-life ($T_{1/2}$) and decay constant ($\lambda$) are related as: [BSEB 2022]

(A) $T_{1/2} = 0.693 / \lambda$

(B) $T_{1/2} = \lambda / 0.693$

(C) $T_{1/2} = 0.693 \lambda$

(D) None of these

116. Nuclear reactor works on the principle of: [BSEB 2021]

(A) Nuclear fusion

(B) Controlled nuclear fission

(C) Uncontrolled nuclear fission

(D) Spontaneous combustion

117. Which of the following is not a fundamental particle? [BSEB 2023]

(A) Electron

(B) Proton

(C) Alpha particle

(D) Neutron

118. In n-type semiconductors, the pentavalent impurity atoms are called: [BSEB 2025]

(A) Donor impurities

(B) Acceptor impurities

(C) Neutral impurities

(D) None of these

119. A p-n junction diode can be used as: [BSEB 2022]

(A) An amplifier

(B) A rectifier

(C) An oscillator

(D) All of these

120. Logic gate which gives high output when both inputs are low is: [BSEB 2024]

(A) AND

(B) OR

(C) NOR

(D) NAND

121. The process of regaining the information from a carrier wave is: [BSEB 2021]

(A) Modulation

(B) Demodulation

(C) Propagation

(D) Transmission

122. Ground waves are used for: [BSEB 2025]

(A) Short-range communication

(B) Long-range communication

(C) Satellite communication

(D) None of these

123. The color of light is determined by its: [BSEB 2018]

(A) Frequency

(B) Amplitude

(C) Speed in vacuum

(D) Intensity

124. Speed of light is maximum in: [BSEB 2021]

(A) Glass

(B) Water

(C) Air

(D) Vacuum

125. Torque experienced by an electric dipole of moment $\vec{p}$ in field $\vec{E}$ is: [BSEB 2022]

(A) $\vec{p} \times \vec{E}$

(B) $\vec{p} \cdot \vec{E}$

(C) $pE$

(D) $p/E$

126. Equivalent capacitance in parallel combination of $n$ capacitors is: [BSEB 2023]

(A) $C_p = n C$

(B) $C_p = C / n$

(C) $C_p = n^2 C$

(D) $C_p = C / n^2$

127. 1 Joule/Coulomb is equal to: [BSEB 2021]

(A) 1 Watt

(B) 1 Volt

(C) 1 Ohm

(D) 1 Ampere

128. Carbon resistor code for “Black” color is: [BSEB 2020]

(A) 0

(B) 1

(C) 2

(D) 3

129. Energy stored in a capacitor is: [BSEB 2022]

(A) $1/2 CV^2$

(B) $CV^2$

(C) $1/2 C^2 V$

(D) $1/2 V^2 C$

130. Unit of specific resistance is: [BSEB 2024]

(A) Ohm/meter

(B) Ohm-meter

(C) Ohm/meter$^2$

(D) (Ohm-meter)$^{-1}$

131. Drift velocity $v_d$ of electrons is of the order of: [BSEB 2021]

(A) $10^{-4}$ m/s

(B) $10^8$ m/s

(C) $10^{-2}$ m/s

(D) $10^6$ m/s

132. Resistance of a semiconductor on heating: [BSEB 2025]

(A) Increases

(B) Decreases

(C) Remains constant

(D) None of these

133. S.I. unit of magnetic permeability is: [BSEB 2021]

(A) Henry/meter

(B) Tesla

(C) Ampere/meter

(D) Weber/meter$^2$

134. Susceptibility of vacuum is: [BSEB 2023]

(A) Zero

(B) 1

(C) $\infty$

(D) $-1$

135. Paramagnetic substances have relative permeability: [BSEB 2022]

(A) Slightly greater than 1

(B) Slightly less than 1

(C) Much greater than 1

(D) Equal to 1

136. Shunt is a ______ resistance: [BSEB 2025]

(A) High

(B) Low

(C) Infinite

(D) Zero

137. Self-induction is also called: [BSEB 2021]

(A) Inertia of electricity

(B) Resistance of electricity

(C) Capacitance of electricity

(D) None of these

138. Unit of self-inductance is equivalent to: [BSEB 2022]

(A) Weber/Ampere

(B) Volt-Second

(C) Ohm-Second

(D) All of these

139. Frequency of DC current is: [BSEB 2024]

(A) Zero

(B) 50 Hz

(C) 60 Hz

(D) Infinite

140. Transformers work on: [BSEB 2021]

(A) AC only

(B) DC only

(C) Both AC and DC

(D) None of these

141. Velocity of EM waves in a medium depends on: [BSEB 2025]

(A) Permittivity and Permeability

(B) Intensity

(C) Frequency

(D) None of these

142. Focal length of a lens of power +2.0 D is: [BSEB 2021]

(A) 50 cm

(B) 100 cm

(C) 20 cm

(D) 200 cm

143. Refractive index of water is: [BSEB 2022]

(A) 1.5

(B) 1.33

(C) 2.42

(D) 1.0

144. Resolving power of a microscope increases when: [BSEB 2025]

(A) Wavelength of light decreases

(B) Wavelength of light increases

(C) Focal length increases

(D) None of these

145. Wavefront is a surface where all points are in the same: [BSEB 2024]

(A) Phase

(B) Frequency

(C) Amplitude

(D) Velocity

146. Photoelectric effect shows ______ nature of light: [BSEB 2021]

(A) Particle

(B) Wave

(C) Both

(D) Neither

147. Maximum kinetic energy of photoelectrons depends on: [BSEB 2022]

(A) Frequency of incident light

(B) Intensity of incident light

(C) Work function of metal

(D) Both (A) and (C)

148. For a stable nucleus, the binding energy per nucleon should be: [BSEB 2025]

(A) High

(B) Low

(C) Zero

(D) Negative

149. Atomic number of a nucleus increases in: [BSEB 2023]

(A) Alpha decay

(B) Beta-minus decay

(C) Gamma decay

(D) None of these

150. Base of the transistor is usually: [BSEB 2021]

(A) Thin and lightly doped

(B) Thick and heavily doped

(C) Thin and heavily doped

(D) Thick and lightly doped