Physics Chapter 6 Entry test MCQs
51. Capacitance with air is 10F, if a dielectric of εr = 100 is inserted then new capacitance
a. 10 F
b. 1000 F
c. 100 F
d. 10 µF
52. If the sheet of a bakelite is inserted between the plates of an air capacitor, the capacitance will
a. Increase
b. Decrease
c. become zero
d. REMAINS unchanged
53. A dielectric material must be
a. Insulator
b. Resistor
c. Semi-conductor
d. Good conductor
54. The capacitance of a capacitor is not affected by
a. Area of plates
b. Thickness of plates
c. Distance between plates
d. All of the above
55. The quantity 1/2 εoE2 has the significance of:
a. Energy/volume
b. Energy/farad
c. Energy
d. Energy/coulomb
56. The energy stored between the plates of a capacitor in not represented by
a. U = 2qV
b. U = CV2/2
c. U = qV/2
d. U = q2/2C
57. If the potential difference across then its energy stored in it will be:
a. 16 times
b. 2 times
c. Remains same
d. 4 times
58. If a 10 F capacitor is to have an energy content of 20 J, it must be placed across a potential difference of
a. 9 volts
b. 4 volts
c. 1 volt
d. 2 volts
59. Energy stored in the electric field of a capacitor C when charged from a D.C source of voltage V is equal to joules
a. 0.5 CV
b. 0.5C V2
c. 0.5 CV
d. CV2
60. When 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of
a. 4 joules
b. 2 joules
c. 8 joules
d. 6 joules
61. A capacitor charging and discharging
a. Linearly
b. Rapidly
c. Logarithmically
d. Exponentially
62. If RC is small, then capacitor will be charged and discharged
a. Slowly
b. Quickly
c. With medium speed
d. Both ‘A’ and ‘C’
63. Which of the following statement is true?
a. The current in the dicharging capacitor grows exponentially
b. The current in the discharging capacitor grows linearly
c. The current in the discharging capacitor decreases constantly
d. The current in the discharging capacitor decays exponentially
PAST PAPER MCQS
64. A particle carrying charge of 2e falls through a potential difference of 3.0 V. Calculate the energy required by it:
a. 1.6 x 10-19J
b. 9.6 x 10-19J
c. 6 x 10-19 J
d. 9.1 x 10-19J
65. The work done in moving a unit positive charge from one point to another point against the electric field is a measure of:
a. Intensity of electric field
b. Capacitance
c. Resistance between two points
d. Potential difference between two points
66. Electric intensity is a vector quantity and its direction is
a. At a certain angle
b. Perpendicular to the direction of field
c. Along the direction of force
d. Opposite to the direction of force
67. The magnitude of an electric field between two separated plates can be calculated by the relation
a. ∆V = qod
b. ∆V = Ed
c. E = ∆V
d. ∆V = Ed
68. The capacitor which charges and discharges quickly will have
a. Large value of time constant
b. small value of RC
c. Large value of RC
d. None of these
69. 10 V potential difference is applied across the plates of 1 F capacitor. What is the energy stored in capacitor?
a. 5J
b. 0.5 mJ
c. 50 J
d. 0.05 mJ
70. What will be the effect on the capacitance of a capacitor if area of each plate is doubled with separation between the plates is halved?
a. Capacitance becomes four times
b. Capacitance remains same
c. Capacitance reduces of half
d. Capacitance becomes double
71. What is the charge stored on a 5µF capacitor charged to the potential difference of 12V?
a. 2.4µC
b. 60μC
c. 60.C
d. 2.4C
72. The distance between the plates of a parallel plate capacitor is 2.0 mm and area of each plates is 2m2. A potential difference of 1.0 x 10-4 V is applied across the plates. Find the capacitance.
a. 8.85 x 10-9F
b. 4 x 10-4F
c. 9 x 104F
d. 3.54 x 109F
73. In the direction indicated by an electric field line:
a. The electric field strength must increase
b. The potential must increase
c. The electric field strength must decrease
d. The potential must decrease
74. The potential difference between a pair of similar parallel conducting plates is known. What additional information is needed in order to find the electric field strength between the plates?
a. Permittivity of the medium separation of the plates.
b. Separation of the plates
c. Permittivity of the medium separation and area of plates.
d. Separation and decrease of the plates.
75. The unit of the electric field is:
a. J/C.m
b. N/C
c. V/m
d. All of the above