12th class (Fsc) Physics unit 1 MCQs
51. Gauss’s law can only be applied to:
a. A surface of any shape
b. A curved surface
c. A closed surface
d. A flat surface
52. NC-1 is the SI unit of:
a. Current
b. Force
c. Electric intensity
d. Charge
53. Due to polarization, electric field:
a. First increases then decreases
b. Increases
c. Remain same
d. Decreases
54. If the distance between two point charges is halved, the electric intensity becomes:
a. Double
b. Half
c. 4 times
d. 1/4 times
55. The electric field intensity due to an infinite sheet of charge:
a. → E = 1/2σε₀ ^r
b. → E = σ/2ε₀ ^r
c. → E = σ/ε₀ ^r
d. → E = 2σ/ε₀ ^r
56. The unit of electric intensity other than NC-1 is:
a. VC-1
b. VA-1
c. NC
d. Vm-1
57. The fact that electric field exist in space around an electrical charge is:
a. Intrinstic property of nature
b. Electrical property
c. Extrinstic property of nature
d. Gravitational property
58. Numerical value of permittivity of free space is:
a. 8.85 x 10-12 N-1m-2c2
b. 9 x 109 Nm2c-2
c. 9 x 1012 N-1m-2c2
d. 8.85 x 10-12 Nm-2c-2
59. The concept of an electric field lines is introduced by:
a. Einstein
b. Coulomb
c. Joseph henry
d. Faraday
60. The unit of electric intensity other than NC-1 :
a. v/c
b. V/A
c. N/v
d. v/m
61. If electric lines of force are equally spaced the electric field is:
a. Weak
b. Uniform
c. Strong
d. Non-uniform
62. Two electrons fall through a potential difference of 3 volts, energy gained is:
a. 3eV
b. 1.6×10-19 J
c. 6eV
d. 9.6×10-19 eV
63. If a charged body is moved against the electric field, it will gain:
a. Mechanical energy
b. P.E
c. Electrical potential energy
d. K.E
64. The quantity time constant RC has units of:
a. Capacitance
b. Charge
c. Resistance
d. Time
65. The electric potential at a mid-point in an electric dipole is:
a. 1 V
b. 0 V
c. 1.5 V
d. 0.5 V
66. The electric field created by positive point charge is:
a. Circular
b. Radially inward
c. Radially outward
d. Zero
67. When some dielectric is inserted between the plates of capacitor, then capacitance:
a. Becomes zero
b. Decreases
c. Becomes infinity
d. Increases
68. he negative of the potential gradient is:
a. Potential difference
b. Electrostatic force
c. Electric field intensity
d. Electromotive force
69. One joule is equal to:
a. 6.25 x 10-18 ev
b. 1.6 x 10-19 ev
c. 6.25 x 1018 ev
d. 1.6 x 1019 ev
70. The equation -Δv/Δr is called:
a. Potential barrier
b. Electric potential
c. Potential gradient
d. Electric energy
71. SI unit of permittivity of free space are:
a. c2 N-1 m-1
b. Nm2 c-2
c. c2 N-1 m-2
d. N-1 m2 c-1
72. Electro-Encephalon-Graph (EEG) is the diagnostic test for the working of:
a. Brain
b. Eye
c. Lungs
d. Heart
73. The absolute electric potential at a point distant 20cm from a charge of 2µ C is:
a. 9×103 V
b. 9×102 V
c. 9×104 V
d. 9×103 V
74. An ECG records the between points on human skin generated by electric process in the heart:
a. Pressure
b. Heart beat
c. Voltage
d. Pulse rate
75. Special organ called ampulla of lorenzini that are very sensitive to electric field are found in:
a. Dogs
b. Bats
c. Sharks
d. Cats