MDCAT Electrostatics MCQs

This comprehensive set of MCQs on Electrostatics is designed to cover all essential topics required for success in the Medical and Dental College Admission Test (MDCAT). Focused on key subjects such as Coulomb’s Law, Electric Fields, Electric Potential, Capacitance, and the Behavior of Charges, these MCQs are crafted to help aspiring medical and dental students build a solid understanding of electrostatic principles and their applications in health sciences.

Who should practice Electrostatics MCQs?

Students preparing for the MDCAT who wish to deepen their understanding of electrostatic concepts, which are fundamental for various applications in medical technologies and devices.
Individuals seeking to enhance their knowledge of electric forces, fields, and potentials, crucial for understanding the behavior of charged particles in biological systems.
University students targeting high-yield topics like capacitance and energy storage, and their relevance to medical instrumentation and diagnostics.
Anyone aiming to strengthen their foundational understanding of electrostatics and its implications in health, electrotherapy, and medical imaging techniques.
Candidates focused on developing critical thinking and analytical skills related to electrostatic problems and their applications in real-world medical scenarios.

1. What does Coulomb’s law describe?

A) The relationship between electric field and magnetic field
B) The force between two point charges
C) The energy stored in a capacitor
D) The motion of charged particles in an electric field

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2. In Coulomb’s law, what happens to the force between two charges if the distance between them is doubled?

A) It doubles
B) It remains the same
C) It becomes half
D) It becomes one-fourth

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3. Coulomb’s law is valid in which of the following conditions?

A) In a vacuum only
B) In a material medium only
C) In both vacuum and material medium
D) In high-temperature conditions

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4. The electric field intensity (E) due to a point charge (Q) at a distance (r) is given by which formula?

A) E = kQ/r
B) E = kQ/r²
C) E = Q/r²
D) E = kQr

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5. What is the unit of electric field intensity?

A) Volt
B) Coulomb
C) Newton per coulomb (N/C)
D) Joule

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6. The electric field intensity due to an infinite sheet of charge is…

A) Zero everywhere
B) Constant and uniform
C) Varies with distance
D) Maximum at the edges

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7. What is the formula for the electric field intensity (E) between two oppositely charged parallel plates?

A) E = V/d
B) E = F/q
C) E = kQ/r²
D) E = Q/(ε₀A)

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8. If the potential difference (V) across a capacitor is doubled, what happens to the stored energy (U)?

A) It doubles
B) It triples
C) It quadruples
D) It remains the same

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9. The potential energy (U) stored in a capacitor is given by which formula?

A) U = 1/2 CV²
B) U = CV
C) U = C/V
D) U = 1/2 QV

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10. A parallel plate capacitor is charged by connecting it to a battery. What happens when the battery is removed?

A) The charge remains constant
B) The charge decreases
C) The charge increases
D) The charge becomes zero

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11. The capacitance (C) of a capacitor is defined as the ratio of…

A) Charge to potential difference
B) Potential difference to charge
C) Energy to voltage
D) Voltage to current

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12. What is the unit of capacitance?

A) Farad (F)
B) Coulomb (C)
C) Volt (V)
D) Ampere (A)

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13. The energy stored in a capacitor can be expressed in which of the following ways?

A) U = CV
B) U = 1/2 QV
C) U = Q²/2C
D) All of the above

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14. What is the effect of increasing the distance between the plates of a capacitor?

A) Capacitance increases
B) Capacitance decreases
C) Capacitance remains unchanged
D) Capacitance becomes infinite

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15. In a dielectric material, what happens to the capacitance of a capacitor?

A) It remains constant
B) It decreases
C) It increases
D) It becomes zero

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16. The electric potential (V) due to a point charge (Q) at a distance (r) is given by which formula?

A) V = kQ/r²
B) V = kQ/r
C) V = Q/r
D) V = kQr

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17. The electric field intensity due to a uniformly charged infinite sheet of charge is…

A) E = σ/(2ε₀)
B) E = σ/ε₀
C) E = kQ/r²
D) E = 0

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18. The area of the plates of a parallel plate capacitor is doubled while keeping the distance constant. What happens to the capacitance?

A) It doubles
B) It halves
C) It remains unchanged
D) It becomes four times

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19. What happens to the potential difference across a capacitor when it is discharged?

A) It increases
B) It remains constant
C) It decreases
D) It becomes infinite

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20. In a parallel plate capacitor, if the plate separation is halved while the voltage remains constant, what happens to the electric field intensity?

A) It doubles
B) It halves
C) It remains the same
D) It becomes zero

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21. The energy density (u) in an electric field is given by which formula?

A) u = 1/2 ε₀E²
B) u = ε₀E²
C) u = 1/2 CV²
D) u = Q/V

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22. The charge on a capacitor is directly proportional to…

A) Voltage
B) Electric field
C) Plate area
D) All of the above

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23. What is the role of a dielectric material in a capacitor?

A) To decrease the capacitance
B) To increase the capacitance
C) To conduct electricity
D) To discharge the capacitor

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24. In a capacitor, if the dielectric constant (κ) is increased, what happens to the capacitance?

A) It decreases
B) It remains the same
C) It increases
D) It becomes zero

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25. What is the potential difference across a capacitor when it is fully charged?

A) Equal to the current
B) Equal to zero
C) Equal to the voltage of the power source
D) Depends on the plate area

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26. The electric field intensity (E) between two charged parallel plates is given by which relationship?

A) E = Vd
B) E = V/d
C) E = d/V
D) E = Q/A

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27. When a capacitor is charged, the energy stored in it is…

A) Lost as heat
B) Converted to potential energy
C) Converted to kinetic energy
D) Remains zero

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28. In a capacitor, what does the term ‘capacitance’ refer to?

A) The ability to store charge
B) The ability to conduct electricity
C) The ability to resist current
D) The ability to generate electric field

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29. What happens to the charge stored in a capacitor if the voltage is halved?

A) It doubles
B) It remains the same
C) It halves
D) It quadruples

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30. The process of charging a capacitor involves…

A) Connecting it to a power supply
B) Discharging it
C) Short-circuiting it
D) Isolating it from a circuit

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31. The time constant (τ) of an RC circuit is given by which formula?

A) τ = R × C
B) τ = R/C
C) τ = C/R
D) τ = R + C

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32. What is the shape of the electric field lines around a positive point charge?

A) Circular
B) Radial outward
C) Radial inward
D) Parallel straight lines

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33. In electrostatics, the force between two charges is affected by which of the following factors?

A) The distance between them
B) The magnitude of the charges
C) The medium between the charges
D) All of the above

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34. The dielectric breakdown of a material occurs when…

A) The voltage is too low
B) The voltage exceeds a certain threshold
C) The temperature is too high
D) The charge is too low

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35. A capacitor with a dielectric has a higher capacitance than an empty capacitor because…

A) The dielectric is a conductor
B) The dielectric reduces the electric field
C) The dielectric allows more charge to be stored
D) The dielectric increases the voltage

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36. When a capacitor discharges, the charge on its plates…

A) Increases
B) Decreases over time
C) Remains constant
D) Fluctuates

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37. Which of the following statements is true regarding electric field lines?

A) They can cross each other
B) They indicate the direction of the electric field
C) They are denser in regions of lower electric field strength
D) They are circular in shape

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38. What happens to the electric field between two charged parallel plates if the distance between them is tripled?

A) It remains unchanged
B) It doubles
C) It halves
D) It becomes one-third

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39. The potential energy stored in a capacitor can be converted into what type of energy?

A) Mechanical energy
B) Thermal energy
C) Kinetic energy
D) All of the above

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40. A capacitor is charged and then isolated. What happens to the voltage across the capacitor if it is connected to a resistor?

A) It increases
B) It decreases
C) It remains constant
D) It becomes zero

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41. The capacitance of a parallel plate capacitor is directly proportional to which of the following?

A) The distance between the plates
B) The area of the plates
C) The potential difference
D) The electric field intensity

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42. In an electrostatic field, the equipotential surfaces are…

A) Always horizontal
B) Perpendicular to electric field lines
C) Parallel to electric field lines
D) Variable in shape

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43. The potential difference between two points is defined as…

A) The work done in moving a unit charge from one point to another
B) The force experienced by a unit charge
C) The energy stored in a capacitor
D) The charge per unit area

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44. If two capacitors are connected in series, what happens to the total capacitance?

A) It increases
B) It decreases
C) It remains unchanged
D) It becomes infinite

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45. The energy stored in a capacitor can be calculated using which of the following relationships?

A) U = 1/2 CV²
B) U = CV
C) U = Q/V
D) U = 1/2 QV

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46. The electric field inside a charged conductor in electrostatic equilibrium is…

A) Zero
B) Maximum
C) Minimum
D) Constant

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47. What type of charge distribution creates a uniform electric field?

A) Point charge
B) Line charge
C) Infinite sheet of charge
D) Charged sphere

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48. In an RC circuit, the time constant determines…

A) The maximum charge stored
B) The rate of charging and discharging
C) The voltage applied
D) The capacitance

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49. What effect does a dielectric have on the potential difference across a capacitor when it is inserted?

A) It increases
B) It decreases
C) It remains the same
D) It becomes zero

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50. The total energy stored in two capacitors in series is…

A) The sum of individual energies
B) Equal to the energy of the smallest capacitor
C) Equal to the energy of the largest capacitor
D) Unchanged

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51. In electrostatics, the concept of electric field strength is analogous to which of the following?

A) Electric charge
B) Gravitational field strength
C) Magnetic field strength
D) Thermal energy

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52. A capacitor is said to be fully charged when…

A) The current stops flowing
B) The voltage is at maximum
C) The energy stored is maximum
D) All of the above

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53. The energy stored in a capacitor can be released as…

A) Electrical current
B) Thermal energy
C) Light energy
D) All of the above

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54. The electric field intensity (E) is inversely proportional to…

A) Charge
B) Distance squared
C) Voltage
D) Time

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55. The charging of a capacitor in an RC circuit follows which type of curve?

A) Linear
B) Exponential
C) Quadratic
D) Logarithmic

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56. When discharging, the voltage across a capacitor decreases according to which equation?

A) V = V₀(1 – e^(-t/τ))
B) V = V₀e^(-t/τ)
C) V = V₀(1 + e^(-t/τ))
D) V = V₀

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57. The relationship between capacitance (C), charge (Q), and voltage (V) is expressed as…

A) C = Q/V
B) C = V/Q
C) C = Q + V
D) C = Q – V

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58. The charging and discharging of a capacitor can be described using…

A) Ohm’s Law
B) Kirchhoff’s Law
C) Exponential decay and growth equations
D) Coulomb’s Law

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59. The electric field intensity (E) between two charged plates is directly proportional to…

A) Charge
B) Distance
C) Voltage
D) Capacitance

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60. The potential difference (V) across a capacitor is directly proportional to which of the following?

A) The charge on the capacitor
B) The capacitance
C) The area of the plates
D) The distance between the plates

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61. Which of the following materials is commonly used as a dielectric?

A) Copper
B) Air
C) Rubber
D) Gold

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62. The formula for the electric field due to a charged infinite plane sheet is given by…

A) E = σ/ε₀
B) E = σ/2ε₀
C) E = 2σ/ε₀
D) E = 0

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63. The potential at a point in an electric field is defined as the…

A) Work done per unit charge in bringing a charge from infinity to that point
B) Force experienced by a unit charge
C) Energy stored in a capacitor
D) Charge per unit area

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64. The relationship between the electric field (E) and potential difference (V) can be expressed as…

A) E = V × d
B) E = V/d
C) E = d/V
D) E = V + d

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65. The total capacitance of capacitors in parallel is given by…

A) The sum of individual capacitances
B) The product of individual capacitances
C) The average of individual capacitances
D) The difference of individual capacitances

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66. A capacitor discharges through a resistor. The time taken for the charge to drop to half its initial value is known as…

A) Time constant
B) Half-life
C) Voltage drop time
D) Discharge rate

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67. The electric field inside a conductor is…

A) Constant
B) Varies with distance
C) Zero
D) Maximum

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68. If the charge on a capacitor is doubled, what happens to the energy stored in it?

A) It remains the same
B) It doubles
C) It quadruples
D) It halves

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69. In electrostatics, the force between two charges is described by which law?

A) Ampere’s Law
B) Faraday’s Law
C) Coulomb’s Law
D) Ohm’s Law

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70. Which of the following factors affects the capacitance of a capacitor?

A) The area of the plates
B) The distance between the plates
C) The type of dielectric
D) All of the above

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71. The electric field intensity (E) due to a point charge is inversely proportional to…

A) Charge
B) Distance
C) Voltage
D) Time

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72. In a parallel plate capacitor, if the plate area is increased while keeping the distance constant, the capacitance…

A) Increases
B) Decreases
C) Remains the same
D) Becomes zero

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73. The potential difference across a capacitor is directly proportional to which of the following?

A) The charge stored
B) The area of the plates
C) The dielectric constant
D) The distance between the plates

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74. A parallel plate capacitor is charged with a voltage of 10V. If the voltage is doubled, the stored energy…

A) Increases by a factor of two
B) Increases by a factor of four
C) Remains the same
D) Decreases

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75. The electric field due to a charged sheet is…

A) Variable with distance
B) Zero
C) Constant
D) Depends on the charge distribution

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76. The electric field intensity between two parallel plates is given by…

A) E = V/d
B) E = d/V
C) E = V + d
D) E = V × d

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77. A capacitor in a circuit can be described as…

A) A source of electric current
B) A temporary storage of electrical energy
C) A resistor
D) A conductor

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78. The dielectric constant of a material is a measure of its ability to…

A) Conduct electricity
B) Store electrical energy
C) Insulate
D) Reduce the electric field

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79. The relationship between the electric field intensity (E) and charge density (σ) is given by…

A) E = σ/ε₀
B) E = ε₀/σ
C) E = σ²
D) E = σ × ε₀

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80. A capacitor’s time constant (τ) is calculated by which formula?

A) τ = RC
B) τ = R/C
C) τ = C/R
D) τ = VR

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81. When a dielectric is inserted into a capacitor, the capacitance…

A) Increases
B) Decreases
C) Remains unchanged
D) Becomes infinite

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82. The work done to move a charge in an electric field is associated with which of the following?

A) Electric field intensity
B) Electric potential difference
C) Electric charge
D) All of the above

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83. What is the unit of capacitance?

A) Joule
B) Farad
C) Volt
D) Coulomb

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84. The potential difference between two points in an electric field is equal to…

A) The work done on a charge
B) The electric field intensity
C) The distance between the points
D) The charge per unit area

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85. When two capacitors are connected in series, the total capacitance is given by which formula?

A) 1/C = 1/C₁ + 1/C₂
B) C = C₁ + C₂
C) C = C₁ × C₂
D) C = C₁ – C₂

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86. The capacitance of a capacitor can be increased by which method?

A) Reducing the plate area
B) Increasing the distance between the plates
C) Using a dielectric material
D) Reducing the voltage

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87. The energy stored in a capacitor can be released when…

A) The capacitor is fully charged
B) The capacitor is connected to a circuit
C) The capacitor is isolated
D) The capacitor is discharged

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88. In an electrostatic field, the force on a charge is dependent on…

A) The mass of the charge
B) The type of dielectric
C) The strength of the electric field
D) The temperature

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89. The charge stored in a capacitor is proportional to which of the following?

A) Voltage
B) Area
C) Distance between plates
D) Both A and B

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90. The time constant of a capacitor discharging through a resistor indicates…

A) The time taken for the charge to decrease by half
B) The total charge stored
C) The voltage across the capacitor
D) The energy released

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91. The unit of electric field intensity is…

A) Joule per Coulomb
B) Volt per meter
C) Farad
D) Ampere

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92. What is the effect of increasing the plate area of a capacitor?

A) It decreases the capacitance
B) It increases the capacitance
C) It has no effect
D) It decreases the voltage

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93. The energy stored in a capacitor is proportional to the square of which of the following?

A) Charge
B) Voltage
C) Distance
D) Area

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94. The direction of electric field lines indicates…

A) The direction of current flow
B) The direction of positive charge movement
C) The direction of negative charge movement
D) The direction of magnetic fields

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95. In electrostatics, two charges of the same sign…

A) Attract each other
B) Repel each other
C) Have no effect
D) Rotate around each other

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96. The capacitance of a capacitor can be expressed as…

A) C = ε₀(A/d)
B) C = A/ε₀d
C) C = A + d
D) C = ε₀d/A

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97. The potential energy stored in a capacitor is given by the equation…

A) U = 1/2 CV²
B) U = CV
C) U = Q²/2C
D) All of the above

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98. The electric field intensity due to a uniformly charged sphere inside the sphere is…

A) Constant
B) Zero
C) Varies with distance
D) Maximum at the center

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99. The process of charging a capacitor involves…

A) Moving charge against the electric field
B) Allowing current to flow
C) Connecting to a voltage source
D) All of the above

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100. A capacitor can store energy because it…

A) Stores charge
B) Has resistance
C) Produces electric fields
D) Can generate current

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