📌 Introduction: Why Current Electricity Matters for ICSE Class 10

Current Electricity is one of the most important chapters in the ICSE Class 10 Physics syllabus. It forms the foundation for understanding electrical circuits, Ohm’s Law, resistance, potential difference, and electric power. This chapter appears prominently in board examinations and is essential for students planning to pursue science streams in higher education.

At 📚 Dhingra Classes Nashik, we have prepared this comprehensive guide with 75 solved MCQs, 15 short answer questions, and 12 long answer questions covering every concept in Current Electricity. Whether you’re preparing for school tests or ICSE board exams, this article will strengthen your understanding and boost your confidence.

📞 Contact Dhingra Classes for expert coaching in Physics, Chemistry, Mathematics, and all ICSE subjects!

🎯 Part A: 75 Solved Multiple Choice Questions (MCQs) on Current Electricity

⚡ Section 1: Electric Current, Charge & Potential (MCQs 1-15)

Q1. The S.I. unit of electric charge is:
(a) Ampere (b) Coulomb (c) Ohm (d) Volt

✅ Answer: (b) Coulomb
Explanation: The S.I. unit of electric charge is coulomb (C) .

Q2. The charge on an electron is:
(a) +1.6 × 10⁻¹⁹ C (b) -1.6 × 10⁻¹⁹ C (c) -1.6 × 10⁻²⁰ C (d) +1.6 × 10⁻²⁰ C

✅ Answer: (b) -1.6 × 10⁻¹⁹ C
Explanation: An electron carries a negative charge of magnitude 1.6 × 10⁻¹⁹ C .

Q3. The number of electrons in 1 C charge is:
(a) 6.25 × 10¹⁸ (b) 6.25 × 10¹⁹ (c) 1.6 × 10¹⁹ (d) 1.6 × 10¹⁸

✅ Answer: (a) 6.25 × 10¹⁸
Explanation: 1 C = 1/(1.6 × 10⁻¹⁹) = 6.25 × 10¹⁸ electrons .

Q4. Electric current is defined as:
(a) Flow of charge (b) Rate of flow of charge (c) Work done per unit charge (d) Resistance to charge flow

✅ Answer: (b) Rate of flow of charge
Explanation: Current is the rate of flow of charge through a conductor: I = Q/t .

Q5. The S.I. unit of electric current is:
(a) Coulomb (b) Volt (c) Ampere (d) Ohm

✅ Answer: (c) Ampere
Explanation: The S.I. unit of current is ampere (A) .

Q6. Current is measured by an instrument called:
(a) Voltmeter (b) Ammeter (c) Galvanometer (d) Rheostat

✅ Answer: (b) Ammeter
Explanation: An ammeter measures current and is always connected in series .

Q7. Electric potential at a point is defined as:
(a) Work done per unit charge (b) Charge per unit time (c) Resistance per unit length (d) Power per unit charge

✅ Answer: (a) Work done per unit charge
Explanation: Electric potential is the work done in bringing a unit positive charge from infinity to that point .

Q8. The S.I. unit of potential difference is:
(a) Ampere (b) Coulomb (c) Volt (d) Ohm

✅ Answer: (c) Volt
Explanation: The S.I. unit of potential difference is volt (V) .

Q9. One volt is the potential difference when:
(a) 1 J work is done in moving 1 C charge (b) 1 C charge flows in 1 second (c) 1 ohm resistance is offered (d) 1 W power is consumed

✅ Answer: (a) 1 J work is done in moving 1 C charge
Explanation: 1 volt = 1 joule/coulomb .

Q10. Potential difference is measured by:
(a) Ammeter (b) Voltmeter (c) Galvanometer (d) Thermometer

✅ Answer: (b) Voltmeter
Explanation: A voltmeter measures potential difference and is connected in parallel .

Q11. If 300 C charge flows through a conductor in 10 minutes, the current is:
(a) 30 A (b) 0.3 A (c) 0.5 A (d) 5 A

✅ Answer: (c) 0.5 A
Explanation: I = Q/t = 300/600 = 0.5 A .

Q12. The conventional direction of current is:
(a) Same as electron flow (b) Opposite to electron flow (c) Random (d) No direction

✅ Answer: (b) Opposite to electron flow
Explanation: Conventional current flows from positive to negative, opposite to electron flow .

Q13. In metals, current is carried by:
(a) Positive ions (b) Negative ions (c) Free electrons (d) Protons

✅ Answer: (c) Free electrons
Explanation: Metals have free electrons that move to constitute current .

Q14. Electric potential is a:
(a) Vector quantity (b) Scalar quantity (c) Neither (d) Both

✅ Answer: (b) Scalar quantity
Explanation: Electric potential has magnitude only, so it is scalar .

Q15. The work done in moving 5 C charge through a potential difference of 1 V is:
(a) 5 J (b) 0.2 J (c) 1 J (d) 10 J

✅ Answer: (a) 5 J
Explanation: W = Q × V = 5 × 1 = 5 J .

🔬 Section 2: Ohm’s Law & Resistance (MCQs 16-35)

Q16. Ohm’s law states that:
(a) V ∝ I (b) I ∝ V (c) V = IR (d) All of the above

✅ Answer: (d) All of the above
Explanation: Ohm’s Law: V = IR, where I ∝ V at constant temperature .

Q17. The constant in Ohm’s law is called:
(a) Current (b) Potential (c) Resistance (d) Charge

✅ Answer: (c) Resistance
Explanation: Resistance is the constant of proportionality in V = IR.

Q18. The S.I. unit of resistance is:
(a) Volt (b) Ampere (c) Ohm (d) Coulomb

✅ Answer: (c) Ohm
Explanation: The S.I. unit of resistance is ohm (Ω) .

Q19. 1 ohm is equal to:
(a) 1 volt × ampere (b) 1 volt/ampere (c) 1 ampere/volt (d) 1 volt + ampere

✅ Answer: (b) 1 volt/ampere
Explanation: R = V/I, so 1 ohm = 1 volt/ampere .

Q20. The obstruction offered to the flow of current is called:
(a) Current (b) Potential (c) Resistance (d) Charge

✅ Answer: (c) Resistance
Explanation: Resistance is the obstruction to current flow .

Q21. Conductance is the reciprocal of:
(a) Current (b) Voltage (c) Resistance (d) Charge

✅ Answer: (c) Resistance
Explanation: Conductance = 1/Resistance .

Q22. The unit of conductance is:
(a) Ohm (b) Ohm⁻¹ (c) Volt (d) Ampere

✅ Answer: (b) Ohm⁻¹
Explanation: The unit of conductance is ohm⁻¹ or siemens .

Q23. The V-I graph for a metallic conductor at constant temperature is:
(a) Curved (b) Straight line through origin (c) Parabola (d) Circle

✅ Answer: (b) Straight line through origin
Explanation: Metals obey Ohm’s Law, giving a straight line .

Q24. The slope of V-I graph gives:
(a) Conductance (b) Resistance (c) Current (d) Power

✅ Answer: (b) Resistance
Explanation: Slope of V-I graph = Resistance .

Q25. The slope of I-V graph gives:
(a) Resistance (b) Conductance (c) Potential (d) Charge

✅ Answer: (b) Conductance
Explanation: Slope of I-V graph = 1/Resistance = Conductance .

Q26. Ohmic resistors are those which:
(a) Do not obey Ohm’s law (b) Obey Ohm’s law (c) Have zero resistance (d) Have infinite resistance

✅ Answer: (b) Obey Ohm’s law
Explanation: Ohmic resistors follow Ohm’s Law .

Q27. Which of the following is a non-ohmic resistor?
(a) Copper wire (b) Nichrome wire (c) LED (d) Tungsten filament

✅ Answer: (c) LED
Explanation: LEDs, diodes, and transistors are non-ohmic .

Q28. Resistance of a wire is directly proportional to:
(a) Area of cross-section (b) Length (c) Temperature decrease (d) Voltage

✅ Answer: (b) Length
Explanation: R ∝ l (length of conductor) .

Q29. Resistance of a wire is inversely proportional to:
(a) Length (b) Area of cross-section (c) Temperature (d) Voltage

✅ Answer: (b) Area of cross-section
Explanation: R ∝ 1/A (area of cross-section) .

Q30. If the radius of a wire is doubled, its resistance becomes:
(a) Double (b) Half (c) One-fourth (d) Four times

✅ Answer: (c) One-fourth
Explanation: R ∝ 1/A ∝ 1/r², so doubling radius makes resistance one-fourth .

Q31. Which material has the highest resistivity?
(a) Copper (b) Silver (c) Nichrome (d) Aluminum

✅ Answer: (c) Nichrome
Explanation: Nichrome has high resistivity and is used in heating elements .

Q32. The resistance of a conductor increases with:
(a) Decrease in temperature (b) Increase in temperature (c) Increase in length decrease (d) Decrease in area

✅ Answer: (b) Increase in temperature
Explanation: Higher temperature increases collisions, increasing resistance .

Q33. Which wire is used for making standard resistors?
(a) Copper (b) Silver (c) Manganin (d) Aluminum

✅ Answer: (c) Manganin
Explanation: Manganin has high resistivity and negligible temperature coefficient .

Q34. The filament of an electric bulb is made of:
(a) Copper (b) Tungsten (c) Nichrome (d) Iron

✅ Answer: (b) Tungsten
Explanation: Tungsten has high melting point and high resistivity .

Q35. Resistivity of a material depends on:
(a) Length (b) Area (c) Nature of material (d) Shape

✅ Answer: (c) Nature of material
Explanation: Resistivity is a material property independent of dimensions .

🔌 Section 3: Series & Parallel Circuits (MCQs 36-55)

Q36. In a series circuit, the current is:
(a) Different at different points (b) Same at all points (c) Zero (d) Infinite

✅ Answer: (b) Same at all points
Explanation: In series, there is only one path, so current is constant .

Q37. In a parallel circuit, the potential difference is:
(a) Different across each resistor (b) Same across all resistors (c) Zero (d) Infinite

✅ Answer: (b) Same across all resistors
Explanation: In parallel, all resistors are connected across the same two points .

Q38. The equivalent resistance in series is:
(a) R₁ + R₂ + R₃ (b) 1/R₁ + 1/R₂ (c) R₁ × R₂ (d) R₁ – R₂

✅ Answer: (a) R₁ + R₂ + R₃
Explanation: R_series = R₁ + R₂ + R₃ .

Q39. The equivalent resistance in parallel is:
(a) R₁ + R₂ (b) 1/R₁ + 1/R₂ (c) R₁ × R₂ (d) R₁/R₂

✅ Answer: (b) 1/R₁ + 1/R₂
Explanation: 1/R_parallel = 1/R₁ + 1/R₂ + … .

Q40. To get 2 Ω resistance using only 6 Ω resistors, the number required is:
(a) 2 (b) 3 (c) 4 (d) 6

✅ Answer: (b) 3
Explanation: Three 6 Ω resistors in parallel give 6/3 = 2 Ω .

Q41. Two resistors of 6 Ω and 4 Ω in series give equivalent resistance of:
(a) 2.4 Ω (b) 10 Ω (c) 24 Ω (d) 1.5 Ω

✅ Answer: (b) 10 Ω
Explanation: R = 6 + 4 = 10 Ω .

Q42. Two resistors of 6 Ω and 4 Ω in parallel give equivalent resistance of:
(a) 10 Ω (b) 2.4 Ω (c) 24 Ω (d) 5 Ω

✅ Answer: (b) 2.4 Ω
Explanation: 1/R = 1/6 + 1/4 = 5/12, R = 2.4 Ω .

Q43. The equivalent resistance of parallel combination is always:
(a) Greater than largest resistance (b) Less than smallest resistance (c) Equal to largest (d) Zero

✅ Answer: (b) Less than smallest resistance
Explanation: Parallel resistance is always less than the smallest individual resistance .

Q44. Three resistors of 2 Ω, 4 Ω, and 6 Ω in series give:
(a) 12 Ω (b) 6 Ω (c) 2 Ω (d) 4 Ω

✅ Answer: (a) 12 Ω
Explanation: R = 2 + 4 + 6 = 12 Ω.

Q45. A 10 V battery connected across 5 Ω gives current:
(a) 50 A (b) 2 A (c) 0.5 A (d) 5 A

✅ Answer: (b) 2 A
Explanation: I = V/R = 10/5 = 2 A.

Q46. In a series circuit, the potential difference across each resistor is:
(a) Same (b) Proportional to resistance (c) Zero (d) Infinite

✅ Answer: (b) Proportional to resistance
Explanation: V = IR, so V is proportional to R in series.

Q47. The total current in a parallel circuit is:
(a) Same in all branches (b) Sum of branch currents (c) Zero (d) Less than smallest branch current

✅ Answer: (b) Sum of branch currents
Explanation: I_total = I₁ + I₂ + I₃ .

Q48. A fuse wire is made of:
(a) Copper and silver (b) Lead and tin alloy (c) Nichrome (d) Tungsten

✅ Answer: (b) Lead and tin alloy
Explanation: Fuse wire has low melting point .

Q49. The resistance of a wire of length 2 m and area 4 m² with resistivity 4 Ω-m is:
(a) 4 Ω (b) 6 Ω (c) 8 Ω (d) 10 Ω

✅ Answer: (c) 8 Ω
Explanation: R = ρl/A = 4×2/4 = 8 Ω .

Q50. A rheostat is used to:
(a) Measure current (b) Measure voltage (c) Regulate current (d) Store charge

✅ Answer: (c) Regulate current
Explanation: A rheostat is a variable resistance for current control .

Q51. An ammeter should have:
(a) High resistance (b) Low resistance (c) Infinite resistance (d) Zero resistance

✅ Answer: (b) Low resistance
Explanation: Ammeter has low resistance to avoid affecting circuit current .

Q52. A voltmeter should have:
(a) Low resistance (b) High resistance (c) Zero resistance (d) Infinite resistance

✅ Answer: (b) High resistance
Explanation: Voltmeter has high resistance to draw minimal current .

Q53. The p.d. across a 2 Ω resistor carrying 3 A current is:
(a) 1.5 V (b) 6 V (c) 5 V (d) 0.67 V

✅ Answer: (b) 6 V
Explanation: V = IR = 3 × 2 = 6 V.

Q54. If a wire is cut into two equal parts, the resistivity of each part:
(a) Doubles (b) Halves (c) Remains same (d) Becomes zero

✅ Answer: (c) Remains same
Explanation: Resistivity depends on material, not dimensions .

Q55. The current flowing through a 10 Ω resistor with 6 V across it is:
(a) 1.2 A (b) 0.6 A (c) 0.2 A (d) 2 A

✅ Answer: (b) 0.6 A
Explanation: I = V/R = 6/10 = 0.6 A .

💡 Section 4: Electric Power & Energy (MCQs 56-75)

Q56. The S.I. unit of electric power is:
(a) Joule (b) Watt (c) Volt (d) Ampere

✅ Answer: (b) Watt
Explanation: Power is measured in watt (W) .

Q57. 1 watt is equal to:
(a) 1 joule × second (b) 1 joule/second (c) 1 volt/ampere (d) 1 ampere/volt

✅ Answer: (b) 1 joule/second
Explanation: 1 W = 1 J/s .

Q58. The formula for electric power is:
(a) P = V/I (b) P = I²R (c) P = V/I² (d) P = IR

✅ Answer: (b) P = I²R
Explanation: P = VI = I²R = V²/R .

Q59. The commercial unit of electrical energy is:
(a) Joule (b) Watt (c) Kilowatt-hour (d) Newton

✅ Answer: (c) Kilowatt-hour
Explanation: 1 kWh = 3.6 × 10⁶ J .

Q60. One kilowatt-hour is equal to:
(a) 1000 J (b) 3600 J (c) 3.6 × 10⁶ J (d) 3.6 × 10³ J

✅ Answer: (c) 3.6 × 10⁶ J
Explanation: 1 kWh = 1000 W × 3600 s = 3.6 × 10⁶ J .

Q61. The heating effect of current is given by:
(a) H = VIt (b) H = I²Rt (c) H = V²t/R (d) All of the above

✅ Answer: (d) All of the above
Explanation: Joule’s Law: H = I²Rt = VIt = V²t/R .

Q62. The resistance of a 100 W, 220 V bulb is:
(a) 220 Ω (b) 484 Ω (c) 100 Ω (d) 44 Ω

✅ Answer: (b) 484 Ω
Explanation: R = V²/P = 220²/100 = 484 Ω .

Q63. For the same voltage, higher power means:
(a) Higher resistance (b) Lower resistance (c) Same resistance (d) No relation

✅ Answer: (b) Lower resistance
Explanation: R ∝ 1/P for same voltage .

Q64. The safe current limit for a 100 W, 220 V appliance is:
(a) 0.45 A (b) 0.5 A (c) 1 A (d) 2 A

✅ Answer: (b) 0.5 A
Explanation: I = P/V = 100/220 ≈ 0.45 A, safe limit ~0.5 A .

Q65. The energy consumed by a 1000 W appliance in 2 hours is:
(a) 500 kWh (b) 2 kWh (c) 2000 kWh (d) 0.5 kWh

✅ Answer: (b) 2 kWh
Explanation: E = P × t = 1 kW × 2 h = 2 kWh.

Q66. Which has more resistance: a 40 W bulb or 60 W bulb (same voltage)?
(a) 40 W bulb (b) 60 W bulb (c) Same (d) Cannot determine

✅ Answer: (a) 40 W bulb
Explanation: R ∝ 1/P, so lower power = higher resistance .

Q67. The heat produced by a 5 Ω resistor carrying 2 A for 10 s is:
(a) 100 J (b) 200 J (c) 50 J (d) 500 J

✅ Answer: (b) 200 J
Explanation: H = I²Rt = 4 × 5 × 10 = 200 J .

Q68. A fuse is connected in:
(a) Parallel with circuit (b) Series with circuit (c) Either way (d) Not connected

✅ Answer: (b) Series with circuit
Explanation: Fuse is always in series to protect the circuit .

Q69. The resistance of a hot filament is:
(a) Less than cold (b) More than cold (c) Same as cold (d) Zero

✅ Answer: (b) More than cold
Explanation: High temperature increases resistance .

Q70. The power of an appliance rated 220 V, 2 A is:
(a) 110 W (b) 440 W (c) 222 W (d) 220 W

✅ Answer: (b) 440 W
Explanation: P = VI = 220 × 2 = 440 W.

Q71. In India, the domestic AC supply voltage is:
(a) 110 V (b) 220 V (c) 440 V (d) 330 V

✅ Answer: (b) 220 V
Explanation: India uses 220 V domestic supply .

Q72. The resistance of a conductor is inversely proportional to:
(a) Length (b) Area of cross-section (c) Temperature (d) Voltage

✅ Answer: (b) Area of cross-section
Explanation: R ∝ 1/A .

Q73. Which is a good conductor of electricity?
(a) Rubber (b) Glass (c) Silver (d) Wood

✅ Answer: (c) Silver
Explanation: Silver is the best conductor .

Q74. The equivalent resistance of two 3 Ω resistors in parallel is:
(a) 6 Ω (b) 3 Ω (c) 1.5 Ω (d) 9 Ω

✅ Answer: (c) 1.5 Ω
Explanation: 1/R = 1/3 + 1/3 = 2/3, R = 1.5 Ω.

Q75. The current in a circuit is measured by connecting ammeter in:
(a) Parallel (b) Series (c) Both (d) Neither

✅ Answer: (b) Series
Explanation: Ammeter is always connected in series .

✍️ Part B: 15 Solved Short Answer Questions on Current Electricity

Q1. Define electric current and state its S.I. unit.

✅ Answer: Electric current is the rate of flow of electric charge through a conductor. I = Q/t. Its S.I. unit is ampere (A) .

Q2. Define electric potential and state its S.I. unit.

✅ Answer: Electric potential at a point is the amount of work done in bringing a unit positive charge from infinity to that point. Its S.I. unit is volt (V) .

Q3. Define potential difference between two points.

✅ Answer: Potential difference between two points is the work done in moving a unit positive charge from one point to the other. V = W/Q. Its S.I. unit is volt .

Q4. Explain the statement “the potential difference between two points is 1 volt.”

✅ Answer: The potential difference between two points is 1 volt when 1 joule of work is done in moving 1 coulomb of charge from one point to the other .

Q5. Define resistance and state its S.I. unit.

✅ Answer: Resistance is the obstruction offered to the flow of current by a conductor. Its S.I. unit is ohm (Ω) .

Q6. State Ohm’s Law.

✅ Answer: Ohm’s Law states that the current flowing through a conductor is directly proportional to the potential difference across its ends, provided temperature remains constant. V = IR .

Q7. Name the particles responsible for current in metals.

✅ Answer: Free electrons are responsible for the flow of current in metals. The direction of conventional current is opposite to electron flow .

Q8. On what factors does the resistance of a conductor depend?

✅ Answer: Resistance depends on:

1. Length (R ∝ l)

2. Area of cross-section (R ∝ 1/A)

3. Nature of material (resistivity)

4. Temperature (R increases with temperature) .

Q9. How does resistance depend on length?

✅ Answer: Resistance is directly proportional to length (R ∝ l). Longer conductors have more collisions between electrons and ions, increasing resistance .

Q10. How does resistance depend on the radius of a wire?

✅ Answer: Resistance is inversely proportional to the square of radius (R ∝ 1/r²). Doubling the radius makes resistance one-fourth .

Q11. What is the difference between ohmic and non-ohmic resistors?

✅ Answer:

• Ohmic resistors: Obey Ohm’s Law; V-I graph is a straight line through origin (e.g., copper, nichrome).

• Non-ohmic resistors: Do not obey Ohm’s Law; V-I graph is curved (e.g., LED, diode) .

Q12. Why is an ammeter connected in series?

✅ Answer: An ammeter is connected in series so that the entire current of the circuit passes through it. It has low resistance to minimize circuit disturbance .

Q13. Why is a voltmeter connected in parallel?

✅ Answer: A voltmeter is connected in parallel to measure the potential difference across a component. It has high resistance so it draws negligible current .

Q14. What is the commercial unit of electrical energy?

✅ Answer: The commercial unit is kilowatt-hour (kWh). 1 kWh = 3.6 × 10⁶ J. It is the energy consumed by a 1000 W appliance in 1 hour .

Q15. State Joule’s law of heating.

✅ Answer: Joule’s Law states that the heat produced in a conductor is:

• Directly proportional to square of current (I²)

• Directly proportional to resistance (R)

• Directly proportional to time (t)
  H = I²Rt .

📖 Part C: 12 Solved Long Answer Questions on Current Electricity

Q1. State Ohm’s Law and describe an experiment to verify it.

✅ Answer:
Ohm’s Law: The current flowing through a conductor is directly proportional to the potential difference across its ends, provided temperature remains constant. V = IR .

Experiment:

• Connect a battery, key, rheostat, ammeter (series), voltmeter (parallel), and unknown resistor.

• Vary current using rheostat and record V and I.

• Plot V vs I graph — it is a straight line through origin.

• Slope = Resistance .

Q2. Derive the expression for equivalent resistance in series.

✅ Answer:
In series, current (I) is same through all resistors. The total potential difference is:
V = V₁ + V₂ + V₃
Using Ohm’s Law:
IR_s = IR₁ + IR₂ + IR₃
R_s = R₁ + R₂ + R₃ .

Q3. Derive the expression for equivalent resistance in parallel.

✅ Answer:
In parallel, potential difference (V) is same across all resistors. The total current is:
I = I₁ + I₂ + I₃
Using Ohm’s Law:
V/R_p = V/R₁ + V/R₂ + V/R₃
1/R_p = 1/R₁ + 1/R₂ + 1/R₃ .

Q4. Explain the factors affecting resistance of a conductor.

✅ Answer:

1. Length (l): R ∝ l

2. Area (A): R ∝ 1/A

3. Material: Different materials have different resistivity (ρ)

4. Temperature: R increases with temperature
   Formula: R = ρl/A .

Q5. What is resistivity? How does it differ from resistance?

✅ Answer:
Resistivity (ρ) is the resistance of a conductor of unit length and unit area. ρ = RA/l.

• Resistance depends on dimensions (l, A).

• Resistivity depends only on material nature .

Q6. Explain the heating effect of electric current with applications.

✅ Answer:
When current flows through a resistor, electrical energy converts to heat. H = I²Rt.
Applications:

• Electric heater, iron, toaster (high resistance nichrome)

• Fuse wire (low melting point) .

Q7. Calculate the resistance of a wire of length 2 m, area 4 m², resistivity 4 Ω-m.

✅ Answer:
R = ρl/A = (4 × 2)/4 = 8 Ω .

Q8. A 240 V heater draws 5 A. Find its resistance.

✅ Answer:
R = V/I = 240/5 = 48 Ω .

Q9. Three resistors 2 Ω, 4 Ω, 6 Ω are connected in series to 12 V. Find current and voltage across each.

✅ Answer:
R_s = 2 + 4 + 6 = 12 Ω
I = 12/12 = 1 A
V₁ = 2 V, V₂ = 4 V, V₃ = 6 V.

Q10. Two resistors 6 Ω and 3 Ω are in parallel across 6 V. Find total current.

✅ Answer:
1/R_p = 1/6 + 1/3 = 1/2, R_p = 2 Ω
I = 6/2 = 3 A.

Q11. Calculate energy consumed by 1000 W heater in 3 hours in kWh and joules.

✅ Answer:
E = 1 kW × 3 h = 3 kWh
E = 3 × 3.6 × 10⁶ = 1.08 × 10⁷ J .

Q12. Explain why fuse wire is made of lead-tin alloy.

✅ Answer:
Fuse wire requires:

• High resistivity (to generate heat)

• Low melting point (to melt quickly during overload)
  Lead-tin alloy has both properties .

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