General Physics II — 2025 Past Questions

Lagos State University PHY102: 168 questions.

Topics: Current, voltage and resistance, Magnetic fields, Ohm's law and analysis of DC circuits, Capacitance, Lorentz force, Biot-Savart and Ampère's laws, Energy in electric fields, Electric field and potential, Electric charge and its properties, Coulomb's law and superposition, Gauss's law

1. What is the SI unit of electric charge?
   1. Coulomb
   2. Volt
   3. Ampere
   4. Ohm
2. Which law states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them?
   1. Ohm's law
   2. Coulomb's law
   3. Faraday's law
   4. Gauss's law
3. If two charges q₁ = +3 µC and q₂ = −3 µC are placed 2 m apart, what is the magnitude of the force between them? (k = 9 × 10⁹ N m²/C²)
   1. 2.7 × 10⁻² N
   2. 4.05 × 10⁻² N
   3. 3.6 × 10⁻² N
   4. 2.03 × 10⁻² N
4. An electric field is defined as
   1. The force per unit charge
   2. The potential energy per unit charge
   3. The current per unit charge
   4. The voltage per unit distance
5. The electric field inside a conductor in electrostatic equilibrium is
   1. Zero
   2. Constant and non-zero
   3. Equal to the electric potential
   4. Equal to the charge density
6. Which of the following describes the direction of an electric field?
   1. From positive to negative charge
   2. From negative to positive charge
   3. Circular around the charge
   4. Perpendicular to the charge
7. Two point charges q₁ and q₂ are placed 5 cm apart in a vacuum and repel each other with a force of 9 N. If the distance is doubled, what will be the force between them?
   1. 2.25 N
   2. 4.5 N
   3. 1.125 N
   4. 9 N
8. Which of the following is true about the electric potential at a point?
   1. It is the work done in bringing a unit positive charge from infinity to that point
   2. It is the force experienced by a unit charge at that point
   3. It is the current flowing through that point
   4. It is the power dissipated at that point
9. The potential difference between two points in an electric field is 12 V. If a charge of 2 C is moved between these points, what is the work done?
   1. 6 J
   2. 12 J
   3. 24 J
   4. 48 J
10. Which of the following materials would be considered an insulator?
    1. Copper
    2. Glass
    3. Aluminium
    4. Silver
11. In an electric field, the electric flux through a closed surface is proportional to
    1. The charge enclosed by the surface
    2. The distance between the charges
    3. The surface area only
    4. The resistance of the surface
12. What is the potential energy of a charge q = 5 C in a uniform electric field E = 10 N/C at a distance d = 2 m (from the reference point)?
    1. 10 J
    2. 20 J
    3. 100 J
    4. 50 J
13. The force on a charge in a uniform electric field is
    1. Proportional to the square of the charge
    2. Inversely proportional to the charge
    3. Proportional to the charge and the electric field strength
    4. Independent of the charge
14. If a positively charged object is brought close to a neutral conductor without making contact, what will happen?
    1. The conductor will gain a net positive charge
    2. The conductor will gain a net negative charge
    3. The conductor will remain neutral with no change at all
    4. Charges in the conductor will rearrange
15. Which of the following best describes the concept of capacitance?
    1. The ability to store charge
    2. The resistance to the flow of current
    3. The potential difference between two points
    4. The current flowing through a circuit
16. What is the capacitance of a parallel plate capacitor with a plate area of 2 m² and a separation of 1 mm, with air as the dielectric? (ε₀ = 8.85 × 10⁻¹² F/m)
    1. 17.7 nF
    2. 22.2 pF
    3. 35.4 pF
    4. 44.3 pF
17. If a capacitor is connected to a battery and then disconnected, the charge on the capacitor will
    1. Remain the same
    2. Decrease rapidly
    3. Increase steadily
    4. Discharge completely
18. In electrostatics, the potential energy of a system of charges is
    1. The work done to assemble the charges from infinity to their present positions
    2. The kinetic energy of the charges
    3. The heat produced by the charges
    4. The current produced by the charges
19. The work required to move a 5 C charge against an electric field over a distance of 10 m, where the field strength is 15 N/C, is
    1. 750 J
    2. 500 J
    3. 1000 J
    4. 1500 J
20. What happens to the electric field strength (due to a point charge) if the distance from it is halved?
    1. It doubles
    2. It quadruples
    3. It remains the same
    4. It halves
21. What is the SI unit of capacitance?
    1. Farad (F)
    2. Henry (H)
    3. Coulomb (C)
    4. Volt (V)
22. Which of the following describes the capacitance of a capacitor?
    1. The ratio of the charge on each conductor to the potential difference between them
    2. The product of charge and potential difference
    3. The energy stored in the capacitor
    4. The resistance of the capacitor
23. The capacitance of a parallel plate capacitor depends on
    1. The area of the plates and the distance between them
    2. The charge on the plates and the distance between them
    3. The voltage applied and the charge stored
    4. The material of the plates
24. If the distance between the plates of a capacitor is halved, the capacitance will
    1. Double
    2. Halve
    3. Remain the same
    4. Quadruple
25. Which of the following increases the capacitance of a capacitor?
    1. Increasing the area of the plates
    2. Decreasing the distance between the plates
    3. Adding a dielectric material between the plates
    4. All of the above
26. A capacitor is charged to a potential difference of 10 V and stores a charge of 5 C. What is its capacitance?
    1. 0.5 F
    2. 2 F
    3. 5 F
    4. 0.2 F
27. In a series combination of capacitors, the equivalent capacitance is
    1. The sum of the individual capacitances
    2. Less than any of the individual capacitances
    3. The product of the individual capacitances
    4. Equal to the largest individual capacitance
28. In a parallel combination of capacitors, the equivalent capacitance is
    1. The sum of the individual capacitances
    2. Less than the smallest capacitance
    3. Equal to the smallest capacitance
    4. Equal to the average of the capacitances
29. A capacitor stores energy in the form of
    1. Electric field
    2. Magnetic field
    3. Kinetic energy
    4. Heat
30. If the voltage across a capacitor is doubled, the energy stored in the capacitor
    1. Remains the same
    2. Doubles
    3. Quadruples
    4. Halves
31. A 2 F capacitor is connected in series with a 4 F capacitor. What is the equivalent capacitance of the combination?
    1. 6 F
    2. 1.33 F
    3. 0.67 F
    4. 2.67 F
32. A dielectric material is inserted between the plates of a capacitor. How does this affect the capacitance?
    1. Increases it
    2. Decreases it
    3. Has no effect
    4. Reduces it to zero
33. The dielectric constant k is defined as
    1. The ratio of the capacitance with the dielectric to the capacitance without the dielectric
    2. The ratio of charge to voltage in a capacitor
    3. The product of charge and potential difference
    4. The resistance of the dielectric material
34. Two capacitors of 3 F and 6 F are connected in parallel. What is the total capacitance?
    1. 2 F
    2. 9 F
    3. 18 F
    4. 1 F
35. If a 5 F capacitor is charged to 20 V, how much charge is stored on the capacitor?
    1. 25 C
    2. 100 C
    3. 10 C
    4. 0.25 C
36. Which of the following is true about the potential difference across capacitors connected in parallel?
    1. It is the same across all the capacitors
    2. It is different for each capacitor
    3. It depends on the individual capacitances
    4. It is zero
37. The potential energy stored in a 2 F capacitor charged to 5 V is
    1. 25 J
    2. 50 J
    3. 5 J
    4. 12.5 J
38. The energy stored in a capacitor can be increased by
    1. Increasing the capacitance
    2. Increasing the voltage across the plates
    3. Adding a dielectric material
    4. All of the above
39. A parallel plate capacitor of capacitance 8 F is charged to 12 V and then disconnected from the battery. What happens to the voltage across the plates if the distance between the plates is increased while the charge is kept constant?
    1. The voltage decreases
    2. The voltage increases
    3. The voltage remains the same
    4. The voltage becomes zero
40. What is the SI unit of electrical resistance?
    1. Ohm (Ω)
    2. Volt (V)
    3. Ampere (A)
    4. Watt (W)
41. Ohm's law states that the current through a conductor between two points is directly proportional to the
    1. Resistance
    2. Voltage
    3. Power
    4. Charge
42. If the resistance of a conductor is 10 Ω and a current of 2 A flows through it, what is the voltage across the conductor?
    1. 5 V
    2. 10 V
    3. 20 V
    4. 40 V
43. Which of the following materials is typically a good conductor of electricity?
    1. Copper
    2. Rubber
    3. Glass
    4. Wood
44. The total resistance in a series circuit is
    1. Equal to the sum of the individual resistances
    2. Less than the smallest resistance
    3. The product of the individual resistances
    4. Equal to the largest resistance
45. In a parallel circuit, the equivalent resistance is
    1. Equal to the sum of the individual resistances
    2. Less than the smallest resistance in the circuit
    3. Equal to the largest resistance
    4. The product of the resistances
46. A resistor of 5 Ω is connected in series with another resistor of 10 Ω. What is the total resistance of the circuit?
    1. 15 Ω
    2. 5 Ω
    3. 10 Ω
    4. 2 Ω
47. If three resistors of 2 Ω, 4 Ω and 6 Ω are connected in parallel, what is the equivalent resistance?
    1. 12 Ω
    2. 1 Ω
    3. 7.2 Ω
    4. 1.09 Ω
48. Which of the following factors does NOT affect the resistance of a wire?
    1. Length of the wire
    2. Cross-sectional area of the wire
    3. Temperature of the wire
    4. Colour of the wire
49. The resistance of a metallic conductor increases with
    1. An increase in temperature
    2. A decrease in temperature
    3. A decrease in length
    4. A decrease in the resistivity of the material
50. The resistivity of a material is defined as
    1. The resistance per unit length
    2. The resistance per unit area
    3. The resistance of a unit length and unit cross-sectional area of the material
    4. The resistance per unit volume
51. A wire has a resistance of 8 Ω. If the length of the wire is doubled while the material and temperature stay constant, the new resistance will be
    1. 4 Ω
    2. 8 Ω
    3. 16 Ω
    4. 32 Ω
52. If the cross-sectional area of a wire is tripled, what happens to its resistance?
    1. It triples
    2. It doubles
    3. It is reduced to one-third
    4. It remains the same
53. A circuit consists of a 12 V battery and a resistor of 3 Ω. What is the current flowing through the circuit?
    1. 4 A
    2. 3 A
    3. 36 A
    4. 1 A
54. Which of the following is true about the resistivity of a material?
    1. It is independent of the dimensions of the material
    2. It decreases with an increase in length
    3. It increases with an increase in cross-sectional area
    4. It is the same for all materials
55. A wire has a resistance of 5 Ω at 20 °C. If the temperature is increased to 100 °C, its resistance increases to 7 Ω. What is the temperature coefficient of resistance?
    1. 0.005 /°C
    2. 0.01 /°C
    3. 0.02 /°C
    4. 0.05 /°C
56. The power dissipated by a resistor can be calculated using which of the following formulas?
    1. P = IV
    2. P = I²R
    3. P = V²/R
    4. All of the above
57. If the voltage across a 10 Ω resistor is 50 V, what is the power dissipated by the resistor?
    1. 5 W
    2. 250 W
    3. 500 W
    4. 25 W
58. Which of the following describes the behaviour of a superconductor?
    1. It has infinite resistance at low temperatures
    2. It has zero resistance at very low temperatures
    3. It increases resistance with increasing current
    4. It has high resistance at room temperature
59. If two resistors of 4 Ω and 6 Ω are connected in parallel, what is the total resistance?
    1. 2.4 Ω
    2. 5 Ω
    3. 10 Ω
    4. 3.33 Ω
60. Which of the following is a ferromagnetic material?
    1. Copper
    2. Aluminium
    3. Iron
    4. Plastic
61. The magnetic field lines around a straight current-carrying conductor are
    1. Straight lines
    2. Circular
    3. Elliptical
    4. Parabolic
62. According to Ampère's circuital law, the magnetic field around a current-carrying wire is proportional to
    1. The length of the wire
    2. The square of the current
    3. The current
    4. The square of the magnetic field
63. The force on a charged particle moving in a magnetic field is maximum when the particle moves
    1. Parallel to the magnetic field
    2. Perpendicular to the magnetic field
    3. At an angle of 45° to the magnetic field
    4. Opposite to the magnetic field
64. What is the magnetic flux through a loop of area 0.1 m² in a uniform magnetic field of 0.5 T perpendicular to the loop?
    1. 0.05 Wb
    2. 0.5 Wb
    3. 0.1 Wb
    4. 5 Wb
65. Which of the following laws is used to determine the direction of the induced current in a loop?
    1. Ohm's law
    2. Faraday's law
    3. Lenz's law
    4. Coulomb's law
66. A current-carrying loop placed in a magnetic field experiences a torque. This principle is the basis of the
    1. Electric motor
    2. Generator
    3. Transformer
    4. Capacitor
67. The magnetic field inside a long solenoid with 100 turns is 0.2 T when the current is 5 A. What is the length of the solenoid? (μ₀ = 4π × 10⁻⁷ H/m)
    1. 3.14 × 10⁻³ m
    2. 0.1 m
    3. 0.4 m
    4. 0.02 m
68. The Earth's magnetic field is believed to be caused by
    1. The movement of molten iron in its outer core
    2. The rotation of the Earth alone
    3. The atmosphere
    4. The gravitational pull of the moon
69. The unit of magnetic flux is
    1. Tesla
    2. Weber
    3. Ampere
    4. Joule
70. If the length of a bar magnet is doubled (with the same pole strength), its magnetic moment
    1. Doubles
    2. Halves
    3. Remains the same
    4. Becomes zero
71. What is the force on a 2 m long wire carrying a current of 3 A in a magnetic field of 0.5 T perpendicular to the wire?
    1. 3 N
    2. 6 N
    3. 9 N
    4. 12 N
72. Which of the following devices uses the principle of electromagnetic induction?
    1. Transformer
    2. Galvanometer
    3. Ammeter
    4. Voltmeter
73. The magnetic dipole moment of a current loop of area A carrying current I is given by
    1. I/A
    2. IA
    3. I²A
    4. I/A²
74. Which law states that the induced emf in a circuit is directly proportional to the rate of change of magnetic flux through the circuit?
    1. Lenz's law
    2. Faraday's law
    3. Biot–Savart law
    4. Ampère's law
75. A magnetic field exerts a force on a moving charge. This force is called the
    1. Electromagnetic force
    2. Magnetic force
    3. Electrostatic force
    4. Nuclear force
76. A bar magnet is cut into two equal halves (across its length). The magnetic moment of each piece is
    1. Halved
    2. Doubled
    3. Unchanged
    4. Zero
77. The angle of dip at the magnetic equator is
    1. 0°
    2. 45°
    3. 90°
    4. 180°
78. Two parallel wires carry currents of 5 A and 10 A in opposite directions and are 0.1 m apart. What is the force per unit length between the wires? (μ₀ = 4π × 10⁻⁷ T m/A)
    1. 1 × 10⁻⁴ N/m, repulsive
    2. 1 × 10⁻⁴ N/m, attractive
    3. 1 × 10⁻⁵ N/m, repulsive
    4. 1 × 10⁻⁵ N/m, attractive
79. In an a.c. circuit, the voltage and current are generally
    1. In phase
    2. Out of phase
    3. Perpendicular to each other
    4. Always zero
80. The frequency of alternating current in most household circuits (for example in Nigeria) is
    1. 50 Hz
    2. 60 Hz
    3. 100 Hz
    4. 120 Hz
81. The root mean square (RMS) value of an a.c. voltage is
    1. The maximum value of the voltage
    2. The average value of the voltage over a cycle
    3. 1/√2 times the peak value
    4. Twice the peak value
82. In an a.c. circuit containing only a resistor, the current is
    1. In phase with the voltage
    2. Out of phase with the voltage
    3. Lagging the voltage by 90°
    4. Leading the voltage by 90°
83. What is the reactance of a 10 µF capacitor in an a.c. circuit with a frequency of 50 Hz?
    1. 318 Ω
    2. 31.8 Ω
    3. 3180 Ω
    4. 3.18 Ω
84. In a series RLC circuit, resonance occurs when
    1. Inductive reactance equals capacitive reactance
    2. Resistance equals reactance
    3. Voltage equals current
    4. The power factor is zero
85. What is the impedance of a series RLC circuit with R = 10 Ω, L = 0.1 H and C = 100 µF at a frequency of 50 Hz?
    1. 10 Ω
    2. 20 Ω
    3. 14.14 Ω
    4. 50 Ω
86. The power factor in an a.c. circuit is given by
    1. sin θ
    2. cos θ
    3. tan θ
    4. cot θ
87. If the power factor of a circuit is 1, the circuit is
    1. Purely resistive
    2. Purely inductive
    3. Purely capacitive
    4. A combination of inductance and capacitance
88. In a purely inductive circuit, the current
    1. Leads the voltage by 90°
    2. Lags the voltage by 90°
    3. Is in phase with the voltage
    4. Is zero
89. The phase difference between current and voltage in a purely capacitive circuit is
    1. 0°
    2. 90°
    3. 180°
    4. 45°
90. The total impedance in a series circuit containing a resistor and a capacitor is
    1. The sum of their resistances
    2. The sum of their reactances
    3. The vector (phasor) sum of their resistance and reactance
    4. Always equal to zero
91. The average power consumed in an a.c. circuit is given by
    1. P = IV
    2. P = I²R only
    3. P = VI cos θ
    4. P = V²/R only
92. If the peak value of an a.c. current is 10 A, what is its RMS value?
    1. 7.07 A
    2. 5 A
    3. 10 A
    4. 14.14 A
93. The time period of an alternating current is the
    1. Time taken for one complete cycle
    2. Time taken for half a cycle
    3. Inverse of the frequency
    4. Both A and C
94. In a series RLC circuit, the voltage across the resistor is 50 V, across the inductor 30 V and across the capacitor 20 V. What is the total (supply) voltage?
    1. 100 V
    2. 60 V
    3. 0 V
    4. 51 V
95. In an a.c. circuit, if the current lags the voltage by 45°, the circuit is
    1. Purely resistive
    2. Purely inductive
    3. Purely capacitive
    4. A combination of resistance and inductance
96. Which of the following components stores energy in a magnetic field?
    1. Resistor
    2. Capacitor
    3. Inductor
    4. Battery
97. The voltage across an inductor is 100 V when the current through it changes at a rate of 20 A/s. What is the inductance of the inductor?
    1. 25 H
    2. 5 H
    3. 2 H
    4. 10 H
98. The power dissipated in a purely resistive a.c. circuit is
    1. Maximum (the power factor is 1)
    2. Zero
    3. Equal to the power factor
    4. Dependent on the frequency
99. The radio in the picture uses 4 cells of 1.5 V each joined in series. What voltage does the radio require?
    1. 1.5 V
    2. 3.0 V
    3. 6.0 V
    4. 9.0 V
100. When similar poles of two magnets are brought near each other, they will show
     1. Attraction
     2. Repulsion
     3. No effect
     4. None of these

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