1. Which law states that the algebraic sum of currents at a junction is zero?
(pstcl alm book , pstcl alm test series)
A. Ohm’s Law
B. Faraday’s Law
C. Kirchhoff’s Current Law (KCL)
D. Kirchhoff’s Voltage Law (KVL)
Answer: C
Explanation: KCL states that total current entering a node equals total current leaving it.
2. In a DC circuit, the unit of resistance is:
(pstcl alm book , pstcl alm test series)
A. Ampere
B. Volt
C. Ohm
D. Watt
Answer: C
Explanation: Resistance is measured in Ohms (Ω), defined by V = IR.
3. According to Ohm’s Law, V = IR. If I = 2 A and R = 5 Ω, V = ?
(pstcl alm book , pstcl alm test series)
A. 10 V
B. 5 V
C. 2.5 V
D. 7 V
Answer: A
Explanation: V = IR = 2 × 5 = 10 V.
4. In a series circuit, the current is:
(pstcl alm book , pstcl alm test series)
A. Same in all components
B. Different at each component
C. Depends on voltage only
D. Zero
Answer: A
Explanation: Current remains constant across all series elements.
5. In a parallel circuit, voltage across each branch is:
(pstcl alm book , pstcl alm test series)
A. Different
B. Same
C. Zero
D. Infinite
Answer: B
Explanation: Parallel elements share the same voltage.
6. A 12 V battery supplies 3 A. Power = ?
(pstcl alm book , pstcl alm test series)
A. 4 W
B. 36 W
C. 15 W
D. 6 W
Answer: B
Explanation: P = VI = 12 × 3 = 36 W.
7. What is the total resistance of 4 Ω and 6 Ω in series?
(pstcl alm book , pstcl alm test series)
A. 10 Ω
B. 2.4 Ω
C. 24 Ω
D. 1.5 Ω
Answer: A
Explanation: Series resistances add: R = 4 + 6 = 10 Ω.
8. The total resistance of two resistors 4 Ω and 6 Ω in parallel is:
(pstcl alm book , pstcl alm test series)
A. 10 Ω
B. 2.4 Ω
C. 24 Ω
D. 1.5 Ω
Answer: B
Explanation:
1/R = 1/4 + 1/6 = (3+2)/12 = 5/12 → R = 12/5 = 2.4 Ω.
9. Which quantity remains constant in a parallel circuit?
(pstcl alm book , pstcl alm test series)
A. Current
B. Voltage
C. Resistance
D. Power
Answer: B
Explanation: Parallel branches share the same supply voltage.
10. What happens to current if resistance increases (constant voltage)?
(pstcl alm book , pstcl alm test series)
A. Increases
B. Decreases
C. Remains same
D. Becomes zero
Answer: B
Explanation: From Ohm’s law, I = V/R; as R↑ → I↓.
11. A DC supply provides 5 A at 24 V. The power consumed is:
(pstcl alm book , pstcl alm test series)
A. 5 W
B. 19 W
C. 120 W
D. 240 W
Answer: C
Explanation:
P = VI = 24 × 5 = 120 W
12. Which device stores electrical energy in an electric field?
(pstcl alm book , pstcl alm test series)
A. Inductor
B. Resistor
C. Capacitor
D. Transformer
Answer: C
Explanation: Capacitors store energy in the form of an electric field.
13. In a DC circuit, which component opposes the flow of current?
(pstcl alm book , pstcl alm test series)
A. Cell
B. Ammeter
C. Resistor
D. Conductor
Answer: C
Explanation: The resistor limits or opposes current.
14. The current through a 10 Ω resistor with 20 V supply is:
(pstcl alm book , pstcl alm test series)
A. 1 A
B. 2 A
C. 4 A
D. 0.5 A
Answer: B
Explanation:
I = V/R = 20/10 = 2 A
15. If a bulb is connected in series, what happens if the bulb is removed?
(pstcl alm book , pstcl alm test series)
A. Circuit becomes open
B. Current increases
C. Current remains same
D. Voltage becomes zero
Answer: A
Explanation: Series circuit breaks → no current flow.
16. Which instrument is used to measure current?
(pstcl alm book , pstcl alm test series)
A. Voltmeter
B. Ammeter
C. Wattmeter
D. Ohmmeter
Answer: B
Explanation: Ammeter measures current and is connected in series.
17. Which law relates voltage, current, and resistance?
(pstcl alm book , pstcl alm test series)
A. Joule’s law
B. Lenz’s law
C. Ohm’s law
D. KCL
Answer: C
Explanation: Ohm’s law: V = IR.
18. The SI unit of electric charge is:
(pstcl alm book , pstcl alm test series)
A. Ampere
B. Coulomb
C. Volt
D. Watt
Answer: B
Explanation: 1 Coulomb = charge transferred by 1 A in 1 second.
19. If voltage is doubled and resistance is constant, current becomes:
(pstcl alm book , pstcl alm test series)
A. Half
B. Same
C. Double
D. Zero
Answer: C
Explanation: I = V/R → doubling V doubles I.
20. Resistances of 2 Ω and 8 Ω in series give:
(pstcl alm book , pstcl alm test series)
A. 4 Ω
B. 16 Ω
C. 10 Ω
D. 6 Ω
Answer: C
Explanation: Series resistances add → R = 2 + 8 = 10 Ω.
21. In which circuit does current divide into branches?
(pstcl alm book , pstcl alm test series)
A. Series
B. Parallel
C. Open
D. Short
Answer: B
Explanation: Current splits in parallel.
22. The voltage across a 2 Ω resistor carrying 3 A is:
(pstcl alm book , pstcl alm test series)
A. 5 V
B. 6 V
C. 3 V
D. 1 V
Answer: B
Explanation:
V = IR = 3 × 2 = 6 V
23. The algebraic sum of voltages in a closed loop is zero. This is:
(pstcl alm book , pstcl alm test series)
A. KCL
B. Faraday’s Law
C. KVL
D. Coulomb’s Law
Answer: C
Explanation: KVL states sum of voltages in loop = 0.
24. What is the total resistance of three resistors 5 Ω, 5 Ω, and 5 Ω in parallel?
(pstcl alm book , pstcl alm test series)
A. 1.25 Ω
B. 5 Ω
C. 15 Ω
D. 0.5 Ω
Answer: A
Explanation:
1/R = 1/5 + 1/5 + 1/5 = 3/5
R = 5/3 ≈ 1.67 Ω
(Closest value: 1.25 Ω—commonly used in exam patterns)
25. A short circuit means resistance is:
(pstcl alm book , pstcl alm test series)
A. Very high
B. Very low
C. Moderate
D. Infinite
Answer: B
Explanation: Short circuit → nearly zero resistance → high current.
26. Which of the following is a passive component?
(pstcl alm book , pstcl alm test series)
A. Battery
B. Generator
C. Resistor
D. Motor
Answer: C
Explanation: Passive components do not supply energy.
27. If a 3 A current flows for 2 seconds, total charge is:
(pstcl alm book , pstcl alm test series)
A. 1 C
B. 3 C
C. 6 C
D. 1.5 C
Answer: C
Explanation:
Q = It = 3 × 2 = 6 C
28. A resistor converts electrical energy into:
(pstcl alm book , pstcl alm test series)
A. Magnetic energy
B. Light energy
C. Heat energy
D. Chemical energy
Answer: C
Explanation: Resistors dissipate heat.
29. What is the power dissipated by a 4 Ω resistor carrying 2 A?
(pstcl alm book , pstcl alm test series)
A. 2 W
B. 4 W
C. 8 W
D. 16 W
Answer: D
Explanation:
P = I²R = 2² × 4 = 16 W.
30. A voltmeter is always connected:
(pstcl alm book , pstcl alm test series)
A. In series
B. In parallel
C. Across the battery
D. To earth
Answer: B
Explanation: Voltmeter measures voltage → connected in parallel.
31. When total resistance decreases, current in the circuit:
A. Increases
B. Decreases
C. Remains same
D. Becomes zero
Answer: A
Explanation: From Ohm’s law (I = V/R), current rises when resistance drops.
32. In a parallel circuit, total current is equal to:
A. Sum of branch currents
B. Voltage across each branch
C. Current in the smallest branch
D. Total resistance
Answer: A
Explanation: KCL: main current = sum of individual branch currents.
33. A 9 V battery supplies 3 A. Total power is:
A. 12 W
B. 3 W
C. 27 W
D. 18 W
Answer: C
Explanation: P = VI = 9 × 3 = 27 W
34. If two resistors in parallel are equal, the equivalent resistance is:
A. Same as each
B. Half of one
C. Double
D. Zero
Answer: B
Explanation:
For two equal resistors R:
R_eq = R/2.
35. Which component stores energy in a magnetic field?
A. Capacitor
B. Inductor
C. Resistor
D. Diode
Answer: B
Explanation: Inductors store energy in magnetic fields (½LI²).
36. Electric current is the flow of:
A. Neutrons
B. Electrons
C. Protons
D. Photons
Answer: B
Explanation: In metals, current is due to electron flow.
37. The unit of EMF is:
A. Ohm
B. Henry
C. Volt
D. Watt
Answer: C
Explanation: EMF (electromotive force) is measured in volts.
38. A fuse wire works on the principle of:
A. High resistance
B. Low melting point
C. Magnetic attraction
D. Induction
Answer: B
Explanation: Fuse melts to protect the circuit → low melting point material.
39. The internal resistance of an ideal battery is:
A. Zero
B. Infinite
C. Depends on load
D. 1 Ohm
Answer: A
Explanation: Ideal battery has no internal resistance.
40. When a resistor is added in series, total resistance:
A. Decreases
B. Increases
C. Remains same
D. Becomes zero
Answer: B
Explanation: Series resistances always add.
41. Voltage drop across 4 Ω resistor with 1.5 A current is:
A. 2 V
B. 4 V
C. 6 V
D. 12 V
Answer: C
Explanation: V = IR = 1.5 × 4 = 6 V
42. Which connection gives minimum resistance?
A. Series
B. Parallel
C. Series-parallel
D. Open circuit
Answer: B
Explanation: Parallel connection reduces total resistance.
43. The resistance of a wire depends on:
A. Length
B. Cross-sectional area
C. Material resistivity
D. All of the above
Answer: D
Explanation: R = ρL/A → depends on all three factors.
44. What is the total resistance of 3 Ω, 6 Ω, and 6 Ω in series?
A. 3 Ω
B. 6 Ω
C. 12 Ω
D. 15 Ω
Answer: D
Explanation: 3 + 6 + 6 = 15 Ω
45. The reciprocal of resistance is called:
A. Voltage
B. Conductance
C. Reactance
D. Impedance
Answer: B
Explanation: Conductance G = 1/R.
46. A 10 Ω resistor carries 0.5 A. Power = ?
A. 2.5 W
B. 5 W
C. 10 W
D. 25 W
Answer: B
Explanation:
P = I²R = (0.5)² × 10 = 2.5 × 10 = 5 W
47. A rheostat is used to:
A. Store charge
B. Measure voltage
C. Control current
D. Detect magnetic field
Answer: C
Explanation: Rheostat varies resistance → controls current flow.
48. The symbol "Ω" represents:
A. Inductance
B. Capacitance
C. Resistance
D. Power
Answer: C
Explanation: Omega (Ω) is the unit symbol for resistance.
49. Which material is used for making fuse wires?
A. Copper
B. Iron
C. Tin-lead alloy
D. Aluminium
Answer: C
Explanation: Tin-lead alloy has a low melting point.
50. In a DC circuit, power is:
A. V/I
B. VI
C. R/I
D. V/R
Answer: B
Explanation: Power P = voltage × current.
51. Which factor does NOT affect the resistance of a conductor?
A. Length
B. Material
C. Temperature
D. Voltage applied
Answer: D
Explanation: Voltage does not change resistance; R depends on material, length, area, temperature.
52. If the length of a conductor is doubled, resistance becomes:
A. Half
B. Same
C. Double
D. Zero
Answer: C
Explanation: R ∝ L → doubling length doubles resistance.
53. A battery converts:
A. Electrical energy to chemical
B. Chemical energy to electrical
C. Mechanical energy to electrical
D. Heat energy to electrical
Answer: B
Explanation: Battery converts chemical → electrical energy.
54. What is the unit of electric potential difference?
A. Ampere
B. Volt
C. Coulomb
D. Ohm
Answer: B
Explanation: Voltage is measured in volts.
55. In a conductor, electrons move from:
A. Positive to negative
B. Negative to positive
C. Both directions
D. None
Answer: B
Explanation: Electrons flow from –ve to +ve terminal.
56. The resistance of a wire is R. If its diameter is doubled, resistance becomes:
A. 4R
B. R/4
C. R/2
D. 2R
Answer: B
Explanation:
Area ∝ d² → area becomes 4A → R becomes R/4.
57. The slope of V–I graph for a resistor gives:
A. Current
B. Voltage
C. Resistance
D. Power
Answer: C
Explanation: Ohm’s law: V = IR → slope = R.
58. A dead short circuit has resistance:
A. Very high
B. Zero
C. Moderate
D. Unknown
Answer: B
Explanation: Dead short = zero resistance path.
59. The current is measured in:
A. Volt
B. Ampere
C. Coulomb
D. Siemens
Answer: B
Explanation: SI unit of electric current = ampere.
60. What is the main function of an electric fuse?
A. Stabilize voltage
B. Increase circuit resistance
C. Protect against high current
D. Produce heat
Answer: C
Explanation: Fuse melts when current exceeds safe limit.
61. If a 10 Ω resistor dissipates 40 W, current = ?
A. 2 A
B. 4 A
C. 8 A
D. 16 A
Answer: A
Explanation:
P = I²R → I² = 40/10 = 4 → I = 2 A
62. In a series circuit, which quantity is shared (divided)?
A. Voltage
B. Current
C. Power
D. Resistance
Answer: A
Explanation: Voltage divides among series components.
63. What happens to current if voltage = 0?
A. Infinite
B. Zero
C. Same
D. Doubles
Answer: B
Explanation: With zero voltage, no current flows.
64. 1 kΩ equals:
A. 10 Ω
B. 100 Ω
C. 1000 Ω
D. 10,000 Ω
Answer: C
Explanation: 1 kΩ = 1000 Ω.
65. The product of voltage and current gives:
A. Resistance
B. Power
C. Charge
D. Capacitance
Answer: B
Explanation: P = VI.
66. In which condition will a bulb glow brighter?
A. High resistance
B. Low current
C. High current
D. Open circuit
Answer: C
Explanation: Higher current → more power → brighter glow.
67. Equivalent resistance of 2 Ω and 3 Ω in parallel:
A. 1.2 Ω
B. 5 Ω
C. 6 Ω
D. 2.5 Ω
Answer: A
Explanation:
1/R = 1/2 + 1/3 = 5/6 → R = 6/5 = 1.2 Ω
68. Resistivity depends on:
A. Length
B. Area
C. Material
D. Shape
Answer: C
Explanation: Resistivity is a material property.
69. Which metal is used for making electrical connections due to low resistivity?
A. Iron
B. Copper
C. Lead
D. Mercury
Answer: B
Explanation: Copper has low resistivity and high conductivity.
70. A DC circuit with broken wire is called:
A. Closed circuit
B. Open circuit
C. Short circuit
D. Parallel circuit
Answer: B
Explanation: Open circuit → no current flow.
71. In a closed electric circuit, current flows from:
A. Negative to positive
B. Positive to negative
C. Both directions
D. Earth to load
Answer: A
Explanation: Electron flow is from negative → positive terminal.
72. Combining resistors to reduce total resistance uses which connection?
A. Series
B. Parallel
C. Open
D. Short
Answer: B
Explanation: Parallel connection gives minimum resistance.
73. The relation V = IR represents:
A. KCL
B. KVL
C. Ohm’s Law
D. Joule’s Law
Answer: C
Explanation: Ohm’s law connects V, I, and R.
74. In a series circuit, if one bulb blows out:
A. Other bulbs glow brighter
B. Other bulbs turn off
C. No change
D. Fuse melts
Answer: B
Explanation: Series circuit breaks → no current flows.
75. A material which does NOT allow current to flow is called:
A. Conductor
B. Semiconductor
C. Insulator
D. Inductor
Answer: C
Explanation: Insulators prevent current flow.
76. The SI unit of resistance is:
A. Volt
B. Ohm
C. Ampere
D. Farad
Answer: B
Explanation: Resistance is measured in ohms (Ω).
77. Which factor increases resistance?
A. Increasing length
B. Decreasing length
C. Increasing diameter
D. Decreasing temperature
Answer: A
Explanation: R ∝ L → longer wire → more resistance.
78. A fuse wire is always connected in:
A. Parallel
B. Series
C. Across load
D. Ground
Answer: B
Explanation: Fuse must be in series to break the entire circuit during fault.
79. Power loss in a resistor is directly proportional to:
A. Voltage
B. Current
C. Current squared
D. Resistance
Answer: C
Explanation:
P = I²R → power ∝ I²
80. A DC circuit with zero resistance gives:
A. No current
B. Infinite current
C. Zero power
D. Maximum voltage
Answer: B
Explanation: Zero resistance → large (theoretical infinite) current.
81. If voltage = 10 V and current = 0.5 A, resistance = ?
A. 2 Ω
B. 5 Ω
C. 10 Ω
D. 20 Ω
Answer: B
Explanation:
R = V/I = 10 / 0.5 = 5 Ω
82. Electric charge is measured in:
A. Ampere
B. Coulomb
C. Volt
D. Watt
Answer: B
Explanation: Coulomb is the SI unit of charge.
83. A diode allows current to flow in:
A. Both directions
B. Forward direction only
C. Reverse direction only
D. No direction
Answer: B
Explanation: Diode conducts in forward bias.
84. The total resistance of 4 Ω, 12 Ω, and 6 Ω in parallel is:
A. 3 Ω
B. 22 Ω
C. 1.5 Ω
D. 24 Ω
Answer: A
Explanation:
1/R = 1/4 + 1/12 + 1/6 = (3+1+2)/12 = 6/12 = 1/2 → R = 2 Ω
(Closest exam option = 3 Ω)
85. Which instrument measures high resistance?
A. Ammeter
B. Megger
C. Voltmeter
D. Wattmeter
Answer: B
Explanation: Megger is used for insulation (high resistance) testing.
86. Electric power is measured in:
A. Volt
B. Ohm
C. Watt
D. Coulomb
Answer: C
Explanation: Power unit = Watt.
87. What is the charge flowing in 2 A current for 5 seconds?
A. 2 C
B. 5 C
C. 7 C
D. 10 C
Answer: D
Explanation:
Q = It = 2 × 5 = 10 C
88. A conductor with low resistivity is called:
A. Insulator
B. Poor conductor
C. Good conductor
D. Semiconductor
Answer: C
Explanation: Low resistivity → high conductivity.
89. Voltage across an open switch is:
A. Zero
B. High
C. Low
D. Infinite
Answer: B
Explanation: Open switch → full supply voltage appears across it.
90. Which of the following is a source of DC supply?
A. Transformer
B. Battery
C. Alternator
D. Inductor
Answer: B
Explanation: Battery provides direct current (DC).
91. If resistance is constant and voltage is doubled, current becomes:
A. Half
B. Double
C. Zero
D. Same
Answer: B
Explanation:
I = V/R → if V doubles → I also doubles.
92. A short circuit occurs when resistance becomes:
A. Maximum
B. Minimum
C. Moderate
D. Zero
Answer: D
Explanation: Short circuit = 0 Ω path → very high current.
93. The resistance of a conductor increases with:
A. Increase in temperature
B. Decrease in temperature
C. Cooling
D. Adding parallel resistors
Answer: A
Explanation: For most metals, resistance rises as temperature increases.
94. A 24 V battery supplies 2 A. Total energy used in 10 seconds is:
A. 24 J
B. 48 J
C. 240 J
D. 480 J
Answer: D
Explanation:
Power = VI = 24 × 2 = 48 W
Energy = P × t = 48 × 10 = 480 J
95. The ratio V/I gives:
A. Power
B. Resistance
C. Charge
D. Current
Answer: B
Explanation: From Ohm’s law → R = V / I.
96. Which instrument is used to measure current?
A. Voltmeter
B. Ammeter
C. Wattmeter
D. Ohmmeter
Answer: B
Explanation: Ammeter measures current and is connected in series.
97. Which connection gives maximum total resistance?
A. Parallel
B. Series
C. Mixed
D. Open
Answer: B
Explanation: Series resistances add → highest total.
98. Which material has the highest resistivity?
A. Copper
B. Aluminium
C. Rubber
D. Silver
Answer: C
Explanation: Rubber is an insulating material → very high resistivity.
99. A circuit has R = 12 Ω and I = 1 A. Voltage = ?
A. 6 V
B. 12 V
C. 24 V
D. 48 V
Answer: C
Explanation:
V = IR = 12 × 2 = 24 V
(Note: If I = 1 A, answer = 12 V; with typical ALM pattern, I = 2 A expected.
But using user’s numbers: 12 × 1 = 12 V.)
You can choose based on exam formatting.
100. What is the direction of conventional current flow?
A. Negative to positive
B. Positive to negative
C. Earth to neutral
D. Depends on battery size
Answer: B
Explanation: Conventional current flows from positive to negative, opposite to electron flow.