Here’s a bank of 60 multiple-choice questions (MCQs) on the topic of current electricity, tailored for BISE Gujranwala. The questions are categorized into easy, moderate, and tough levels, along with their respective answers at the end.
Easy Questions
1. What is the unit of electric current?
- A) Volt
- B) Ohm
- C) Ampere
- D) Watt
2. The direction of conventional current flows from:
- A) Positive to negative
- B) Negative to positive
- C) East to west
- D) North to south
3. Which instrument is used to measure electric current?
- A) Voltmeter
- B) Ammeter
- C) Ohmmeter
- D) Galvanometer
4. What does the potential difference between two points in a circuit measure?
- A) Resistance
- B) Current
- C) Energy
- D) Voltage
5. The term "electromotive force" (emf) refers to:
- A) The energy supplied per unit charge
- B) The resistance of the circuit
- C) The flow of electrons
- D) The power consumed
6. Ohm's Law states that the current through a conductor is:
- A) Directly proportional to voltage
- B) Inversely proportional to voltage
- C) Independent of voltage
- D) Equal to voltage
7. Which of the following is an example of a non-ohmic conductor?
- A) Copper
- B) Carbon
- C) Aluminum
- D) Nichrome
8. The resistance of a conductor is affected by:
- A) Length
- B) Temperature
- C) Cross-sectional area
- D) All of the above
9. A material that allows electric charges to flow easily is called a:
- A) Insulator
- B) Conductor
- C) Semiconductor
- D) Superconductor
10. In a series circuit, the total resistance is:
- A) The sum of individual resistances
- B) The product of individual resistances
- C) Equal to the highest resistance
- D) Constant
11. What is the formula for calculating electrical power?
- A) P = VI
- B) P = IR
- C) P = V/R
- D) P = I/V
12. Direct current (DC) flows:
- A) In one direction only
- B) Alternates direction
- C) Changes magnitude only
- D) Is always constant
13. Which of the following is NOT a hazard of electricity?
- A) Electric shock
- B) Short circuit
- C) Overheating
- D) Conductivity
14. The safe use of electricity at home involves:
- A) Overloading circuits
- B) Using insulated tools
- C) Ignoring warnings
- D) Mixing water with electrical devices
15. Which of the following is an insulator?
- A) Copper
- B) Silver
- C) Rubber
- D) Aluminum
16. The unit of electrical energy is:
- A) Joule
- B) Watt
- C) Volt
- D) Ampere
17. If the voltage across a resistor is doubled, the current:
- A) Stays the same
- B) Doubles
- C) Halves
- D) Quadruples
18. A voltmeter is used to measure:
- A) Current
- B) Resistance
- C) Voltage
- D) Power
Moderate Questions
19. In a parallel circuit, the voltage across each resistor is:
- A) The same
- B) Different
- C) Half of the total voltage
- D) Zero
20. Which of the following describes ohmic conductors?
- A) Resistance changes with temperature
- B) They follow Ohm's Law
- C) They have infinite resistance
- D) They conduct only AC
21. The electrical energy consumed by an appliance can be calculated using which formula?
- A) Energy = Power × Time
- B) Energy = Voltage × Current
- C) Energy = Current × Resistance
- D) Energy = Power × Resistance
22. When resistors are connected in series, the total voltage is:
- A) Equal to the sum of the individual voltages
- B) Equal to the highest individual voltage
- C) Equal to the lowest individual voltage
- D) Constant
23. What happens to the total resistance in a circuit when resistors are added in parallel?
- A) It increases
- B) It decreases
- C) It remains the same
- D) It doubles
24. The principle behind electrical safety devices like fuses is to:
- A) Increase current flow
- B) Prevent overheating
- C) Increase voltage
- D) Decrease resistance
25. The measure of the opposition that a circuit offers to the flow of electric current is known as:
- A) Voltage
- B) Current
- C) Resistance
- D) Power
26. A circuit that has only one path for current flow is called:
- A) Parallel circuit
- B) Series circuit
- C) Open circuit
- D) Short circuit
27. The resistance of a wire is directly proportional to:
- A) Its length
- B) Its diameter
- C) The material's conductivity
- D) The temperature
28. A charge of 2 Coulombs moves through a potential difference of 4 Volts. What is the energy transferred?
- A) 2 Joules
- B) 4 Joules
- C) 8 Joules
- D) 16 Joules
29. The term "joule's law" relates to:
- A) Heat produced by electric current
- B) Voltage across a conductor
- C) Magnetic fields
- D) Capacitance
30. A conductor with a higher temperature typically has:
- A) Lower resistance
- B) Higher resistance
- C) Constant resistance
- D) No resistance
31. Which type of current alternates direction periodically?
- A) Direct current
- B) Alternating current
- C) Pulsating current
- D) Steady current
32. The electrical power consumed by an appliance rated at 100 Watts operating for 2 hours is:
- A) 100 Joules
- B) 200 Joules
- C) 200 Watts
- D) 200 Watt-hours
33. The energy in a circuit can be increased by:
- A) Decreasing the voltage
- B) Increasing the current
- C) Using insulators
- D) Using a shorter wire
34. If the resistance of a circuit is halved, the current will:
- A) Stay the same
- B) Double
- C) Half
- D) Quadruple
35. Which of the following is an example of a series connection?
- A) Christmas lights
- B) Car headlights
- C) Home wiring
- D) Circuit boards
36. A capacitor stores electrical energy in the form of:
- A) Magnetic field
- B) Electric field
- C) Thermal energy
- D) Chemical energy
Tough Questions
37. When calculating the total resistance in a parallel circuit, the formula used is:
- A) R_total = R1 + R2 + R3
- B) 1/R_total = 1/R1 + 1/R2 + 1/R3
- C) R_total = R1 × R2 × R3
- D) R_total = (R1 + R2 + R3)/3
38. The potential difference across a 10-ohm resistor carrying a current of 2 Amperes is:
- A) 10 Volts
- B) 20 Volts
- C) 5 Volts
- D) 2 Volts
39. A 60-Watt bulb is connected to a 120-Volt source. What is the current flowing through the bulb?
- A) 0.5 A
- B) 1 A
- C) 2 A
- D) 4 A
40. If the current in a circuit is tripled while the resistance remains constant, the voltage:
- A) Stays the same
- B) Triples
- C) Halves
- D) Quadruples
41. Which of the following materials would have the highest conductivity?
- A) Wood
- B) Rubber
- C) Copper
- D) Glass
42. The relationship between voltage, current, and resistance is represented by:
- A) Kirchhoff's Law
- B) Faraday's Law
- C) Ohm's Law
- D) Ampere's Law
43. When a circuit breaker trips, it:
- A) Increases resistance
- B) Decreases current
- C) Breaks the circuit
- D) Reduces voltage
44. A load in an electrical circuit refers to:
- A) The source of energy
- B) The current flow
- C) The component that consumes power
- D) The circuit connections
45. The energy consumed by an electric device is measured in:
- A) Watts
- B) Kilowatt-hours
- C) Amperes
- D) Joules per second
46. A resistor in a circuit is used to:
- A) Increase current
- B) Reduce voltage
- C) Control current flow
- D) Store energy
47. An insulator is defined as a material that:
- A) Allows electric current to flow easily
- B) Resists the flow of electric current
- C) Stores electric charge
- D) Has no electrical charge
48. The SI unit of electromotive force (emf) is:
- A) Volt
- B) Ampere
- C) Ohm
- D) Watt
49. What effect does increasing the temperature of a conductor generally have on its resistance?
- A) It decreases resistance
- B) It increases resistance
- C) It has no effect
- D) It makes it a superconductor
50. The term "short circuit" refers to:
- A) A connection with high resistance
- B) An unintended low-resistance connection
- C) A safe circuit design
- D) A type of fuse
51. In an AC circuit, the maximum value of current is known as:
- A) RMS current
- B) Peak current
- C) Average current
- D) Instantaneous current
52. Which of the following is a characteristic of an ohmic conductor?
- A) Non-linear I-V characteristic
- B) Linear I-V characteristic
- C) High-temperature dependency
- D) Voltage-independent resistance
53. The formula for electrical energy consumed in kilowatt-hours is:
- A) Energy = Power × Time
- B) Energy = Voltage × Current × Time
- C) Energy = Current × Resistance × Time
- D) Energy = Power × Voltage
54. A device that automatically interrupts the current flow in case of an overload is known as:
- A) Fuse
- B) Circuit breaker
- C) Relay
- D) Switch
55. If the length of a conductor is doubled, the resistance:
- A) Doubles
- B) Halves
- C) Remains the same
- D) Quadruples
56. In a typical household circuit, what is the standard voltage supply?
- A) 110 V
- B) 120 V
- C) 220 V
- D) 240 V
57. Which law can be used to determine the total current in a parallel circuit?
- A) Kirchhoff's Current Law
- B) Ohm's Law
- C) Faraday's Law
- D) Ampere's Law
58. The process by which electrical energy is converted to heat energy in a conductor is called:
- A) Induction
- B) Resistance heating
- C) Capacitive heating
- D) Electrical conduction
59. In a series circuit with three resistors, if one resistor fails, the current:
- A) Continues to flow
- B) Stops flowing
- C) Increases
- D) Decreases
60. The power factor in an AC circuit is defined as the ratio of:
- A) Real power to apparent power
- B) Apparent power to reactive power
- C) Reactive power to real power
- D) Real power to voltage
Answers:
1. C
2. A
3. B
4. D
5. A
6. A
7. B
8. D
9. B
10. A
11. A
12. A
13. D
14. B
15. C
16. A
17. B
18. C
19. A
20. B
21. A
22. A
23. B
24. B
25. C
26. B
27. A
28. C
29. A
30. B
31. B
32. D
33. B
34. B
35. A
36. B
37. B
38. B
39. A
40. B
41. C
42. C
43. C
44. C
45. B
46. C
47. B
48. A
49. B
50. B
51. B
52. B
53. A
54. B
55. A
56. C
57. A
58. B
59. B
60. A