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CBSE Class 10 Science Chapter 11 Electricity — 20 MCQs with Answers

Electricity is one of the most scoring chapters in CBSE Class 10 Science, yet MCQs here can trip you up if you confuse similar-sounding formulas or misread circuit diagrams. The 2025 board paper awards roughly 6–8 marks to this chapter, with 2–3 MCQs worth 1 mark each and a numerical problem worth 2–3 marks. Below are 20 carefully selected MCQs that mirror CBSE's competency-based blueprint: factual recall, conceptual application, and higher-order thinking. Work through them section-wise, check your answers immediately, and revisit weak spots in your NCERT textbook.

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Key takeaways

  • ✓Chapter 11 Electricity typically carries 6–8 marks in the CBSE Class 10 Science board paper, with 2–3 MCQs and at least one numerical problem.
  • ✓Ohm's law (V = IR) and its graphical representation are high-frequency MCQ topics; expect one direct or application-based question every year.
  • ✓Series and parallel resistance formulas must be on your fingertips: series Rs = R₁ + R₂ + R₃, parallel 1/Rp = 1/R₁ + 1/R₂ + 1/R₃.
  • ✓Heating effect (H = I²Rt) and power (P = VI = I²R = V²/R) appear in both MCQ and numerical formats; unit conversions (kW, kWh) are tested.
  • ✓Assertion-Reason MCQs now form part of the competency-based pattern; practice linking cause-and-effect statements from NCERT text.
  • ✓Resistivity (ρ = RA/l) is conceptually tested — distinguish between resistance (device-specific) and resistivity (material property).
  • ✓Practise these 20 MCQs under timed conditions to build exam confidence; CBSETUTOR.ai offers unlimited AI-generated MCQ sets and instant photo-upload doubt-solving at ₹999/month for Classes 6–12.

Ohm's Law and V-I Characteristics

Ohm's law states that the potential difference V across a conductor is directly proportional to the current I flowing through it, provided temperature remains constant: V = IR. The constant of proportionality is resistance R, measured in ohms (Ω). The V-I graph for an ohmic conductor (like a metallic wire) is a straight line passing through the origin, indicating constant resistance. Non-ohmic devices such as diodes or filament bulbs show curved graphs. CBSE often tests whether you can identify ohmic behaviour from a graph or calculate R given V and I. Remember that resistance depends on material (resistivity), length, and cross-sectional area but is independent of V and I for ohmic conductors.
  • Q1. A wire of resistance 10 Ω carries a current of 2 A. The potential difference across it is: (A) 5 V (B) 12 V (C) 20 V (D) 0.2 V
  • Answer: (C) 20 V. Using Ohm's law V = IR = 2 × 10 = 20 V.
  • Q2. Which graph represents Ohm's law for a metallic conductor at constant temperature? (A) Parabola (B) Hyperbola (C) Straight line through origin (D) Curved line not through origin
  • Answer: (C) Straight line through origin. V ∝ I for an ohmic conductor, so the graph is linear and passes through the origin.
  • Q3. If the current through a resistor is doubled, the potential difference across it will: (A) remain same (B) become half (C) become double (D) become four times
  • Answer: (C) become double. V = IR; if I doubles and R is constant, V also doubles.
  • Q4. The resistance of a conductor is independent of: (A) length (B) area of cross-section (C) temperature (D) potential difference applied
  • Answer: (D) potential difference applied. For an ohmic conductor, R is constant and does not change with V or I; it depends on material, length, area, and temperature.

Resistance and Resistivity Concepts

Resistance R of a conductor is given by R = ρl/A, where ρ (rho) is resistivity, l is length, and A is cross-sectional area. Resistivity is an intrinsic property of the material and has SI unit ohm-metre (Ω·m). Metals have low resistivity (copper ~1.7 × 10⁻⁸ Ω·m) while insulators have high resistivity. CBSE Class 10 Science Electricity MCQs often ask you to compare resistance when length or area changes, or to distinguish between resistance (device-specific) and resistivity (material property). Note that resistivity increases with temperature for most conductors. Alloys like nichrome and manganin have higher resistivity than pure metals and are used in heating elements and standard resistors respectively.
  • Q5. The SI unit of resistivity is: (A) ohm (B) ohm-metre (C) ampere (D) volt-metre
  • Answer: (B) ohm-metre. Resistivity ρ = RA/l, so unit = Ω·m²/m = Ω·m.
  • Q6. A wire of length l and resistance R is stretched to double its length. Its new resistance becomes: (A) R/2 (B) R (C) 2R (D) 4R
  • Answer: (D) 4R. When stretched, volume remains constant: A₁l₁ = A₂l₂. If l₂ = 2l₁, then A₂ = A₁/2. New R₂ = ρ(2l)/(A/2) = 4ρl/A = 4R.
  • Q7. Which material is chosen for making heating elements of electrical appliances? (A) Copper (B) Silver (C) Nichrome (D) Aluminium
  • Answer: (C) Nichrome. It has high resistivity and high melting point, so it does not melt easily and produces large heat per unit length.
  • Q8. If the area of cross-section of a wire is halved keeping length and material same, its resistance will: (A) remain same (B) become half (C) become double (D) become four times
  • Answer: (C) become double. R = ρl/A; if A is halved, R doubles.

Series and Parallel Combination of Resistors

When resistors are connected in series, the current through each is the same and the total potential difference is the sum: V = V₁ + V₂ + V₃. Equivalent resistance Rs = R₁ + R₂ + R₃; it is always greater than the largest individual resistor. In parallel combination, the potential difference across each resistor is the same and the total current is the sum: I = I₁ + I₂ + I₃. Equivalent resistance is given by 1/Rp = 1/R₁ + 1/R₂ + 1/R₃; Rp is always less than the smallest resistor. NCERT Class 10 Science MCQ questions frequently test your ability to calculate equivalent resistance or identify whether a given circuit is series or parallel. Mixed circuits require step-by-step simplification.
  • Q9. Three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in series. Their equivalent resistance is: (A) 0.1 Ω (B) 1.03 Ω (C) 10 Ω (D) 30 Ω
  • Answer: (C) 10 Ω. In series, Rs = 2 + 3 + 5 = 10 Ω.
  • Q10. Two resistors of 4 Ω each are connected in parallel. The equivalent resistance is: (A) 8 Ω (B) 4 Ω (C) 2 Ω (D) 1 Ω
  • Answer: (C) 2 Ω. For two equal resistors in parallel, Rp = R/2 = 4/2 = 2 Ω. Alternatively 1/Rp = 1/4 + 1/4 = 2/4, so Rp = 2 Ω.
  • Q11. In a series circuit, if one bulb fuses, the other bulbs will: (A) glow brighter (B) glow dimmer (C) not glow (D) remain unaffected
  • Answer: (C) not glow. In series, the same current flows through all components; if the circuit breaks at one point, current becomes zero everywhere.
  • Q12. The equivalent resistance of three resistors 6 Ω, 3 Ω, and 2 Ω connected in parallel is: (A) 11 Ω (B) 1 Ω (C) 0.5 Ω (D) 2 Ω
  • Answer: (B) 1 Ω. 1/Rp = 1/6 + 1/3 + 1/2 = 1/6 + 2/6 + 3/6 = 6/6 = 1, so Rp = 1 Ω.

Heating Effect of Electric Current

When current flows through a resistor, electrical energy is converted into heat energy. The heat produced H = I²Rt joules, where I is current in amperes, R is resistance in ohms, and t is time in seconds. This is also called Joule heating. Devices like electric irons, geysers, and toasters work on this principle. The power P (rate of heat production) is P = I²R = VI = V²/R watts. One kilowatt-hour (kWh or unit) is the energy consumed by a 1 kW appliance in one hour: 1 kWh = 3.6 × 10⁶ J. CBSE Class 10 Science chapter 11 quiz questions often involve calculating heat produced or energy consumed, so practice unit conversions carefully. Fuses and circuit breakers also use the heating effect to protect circuits from overcurrent.
  • Q13. A current of 2 A flows through a 5 Ω resistor for 10 seconds. The heat produced is: (A) 20 J (B) 100 J (C) 200 J (D) 400 J
  • Answer: (C) 200 J. H = I²Rt = 2² × 5 × 10 = 4 × 5 × 10 = 200 J.
  • Q14. An electric iron of resistance 20 Ω draws a current of 5 A. The power consumed is: (A) 100 W (B) 250 W (C) 500 W (D) 1000 W
  • Answer: (C) 500 W. P = I²R = 5² × 20 = 25 × 20 = 500 W.
  • Q15. The commercial unit of electrical energy is: (A) watt (B) joule (C) kilowatt-hour (D) watt-second
  • Answer: (C) kilowatt-hour. It is commonly called a 'unit' on electricity bills; 1 kWh = 1000 W × 3600 s = 3.6 × 10⁶ J.
  • Q16. A 100 W bulb is used for 5 hours daily. The energy consumed in 30 days is: (A) 15 kWh (B) 150 kWh (C) 1.5 kWh (D) 1500 kWh
  • Answer: (A) 15 kWh. Energy = Power × time = 100 W × 5 h/day × 30 days = 15000 Wh = 15 kWh.

Electric Power and Its Applications

Electric power P is the rate at which electrical energy is consumed or supplied. Its SI unit is the watt (W), and 1 W = 1 J/s. The three power formulas are P = VI, P = I²R, and P = V²/R; choose the appropriate one depending on what is given. Appliances are rated by their power and voltage, e.g. '60 W, 220 V' means the bulb consumes 60 W when connected to 220 V supply. Current drawn I = P/V = 60/220 ≈ 0.27 A. Higher-wattage devices consume more energy in the same time. CBSE Electricity important questions Class 10 often compare two bulbs or heaters in terms of power, resistance, or brightness. Remember: for a given voltage, higher power means lower resistance and vice versa.
  • Q17. Two bulbs of 40 W and 60 W are connected in series to a 220 V supply. Which bulb will glow brighter? (A) 40 W (B) 60 W (C) Both equally (D) Neither
  • Answer: (A) 40 W. In series, current is same. Power P = I²R, so the bulb with higher resistance glows brighter. R = V²/P, so R₄₀ > R₆₀, hence 40 W bulb is brighter.
  • Q18. The power of a lamp is 100 W and it operates at 200 V. The resistance of its filament is: (A) 2 Ω (B) 20 Ω (C) 200 Ω (D) 400 Ω
  • Answer: (D) 400 Ω. P = V²/R, so R = V²/P = 200²/100 = 40000/100 = 400 Ω.
  • Q19. If the voltage across a resistor is doubled, the power dissipated becomes: (A) half (B) same (C) double (D) four times
  • Answer: (D) four times. P = V²/R; if V doubles, P becomes (2V)²/R = 4V²/R = 4P.
  • Q20. Which device has the highest power rating in a typical household? (A) LED bulb 9 W (B) Tube light 40 W (C) Ceiling fan 75 W (D) Electric iron 1000 W
  • Answer: (D) Electric iron 1000 W. Heating appliances like irons, geysers, and ovens have wattages in kilowatts, far higher than lighting or fans.

How to Attempt MCQs in the CBSE Board Paper

CBSE Class 10 Science papers now include 20 MCQs carrying 1 mark each in Section A. For Chapter 11 Electricity, expect 2–3 MCQs covering Ohm's law, resistance formulas, series-parallel circuits, heating effect, and power. Read each question twice; many mark losses happen because students misread 'series' as 'parallel' or confuse R = V²/P with P = V²/R. Underline keywords like 'doubled', 'halved', 'constant', and 'independent of'. For numerical MCQs, substitute values carefully — write units to avoid confusion between W and kW, s and h. Assertion-Reason MCQs require you to evaluate two statements separately and then check if the reason correctly explains the assertion; both may be true yet unrelated. Eliminate obviously wrong options first; if stuck, use dimensional analysis or limiting cases. Do not spend more than 45 seconds per MCQ; mark doubtful ones and return if time permits. Accuracy matters more than speed in Section A, as negative marking is absent but every mark counts toward your final percentage.
  • Read the question stem completely before scanning options; CBSE often places the correct answer as option C or D to test patience.
  • For formula-based MCQs, jot down the formula in the margin (e.g. H = I²Rt) to avoid mental errors under exam stress.
  • If two options are numerically close, recheck your calculation or unit conversion — a factor of 10 or 100 often separates correct from incorrect.
  • In circuit diagram MCQs, redraw the circuit in simplified form; replace series and parallel blocks step-by-step to find equivalent resistance.
  • Assertion-Reason format: first decide if A is true, then if R is true, then if R explains A. All four combinations are possible.
  • Use your NCERT textbook's in-text questions and back-exercise MCQs as gold-standard practice; CBSE lifts language and values directly from NCERT.
  • If you are stuck on an MCQ during practice, upload a photo to CBSETUTOR.ai and get an instant step-by-step solution with concept notes — available 24×7 at ₹999/month for all of Classes 6–12, with a 3-day free trial.

Frequently asked questions

How many MCQs from Chapter 11 Electricity appear in the CBSE Class 10 board exam?+
Typically 2–3 MCQs worth 1 mark each appear in Section A. Additionally, expect one 2-mark and one 3-mark numerical or conceptual question in Sections B and C, bringing the chapter total to 6–8 marks.
Are these 20 MCQs enough to score full marks in Electricity MCQs?+
These 20 cover all key concepts, but supplement them with NCERT in-text questions, exemplar problems, and previous years' board papers. CBSETUTOR.ai generates unlimited fresh MCQ sets so you never run out of practice material.
What is the difference between resistance and resistivity?+
Resistance R is a property of a specific conductor (depends on length, area, material) measured in ohms. Resistivity ρ is an intrinsic material property (independent of dimensions) measured in ohm-metre. Formula: R = ρl/A.
Which formula for power should I use — P = VI, P = I²R, or P = V²/R?+
Use P = VI when both voltage and current are given. Use P = I²R when current and resistance are known (e.g. heating effect problems). Use P = V²/R when voltage and resistance are known (e.g. comparing two bulbs rated at same voltage).
Why does a 40 W bulb glow brighter than a 60 W bulb in a series circuit?+
In series, current is the same through both. Power P = I²R, so the bulb with higher resistance glows brighter. Since R = V²/P (at rated voltage), the 40 W bulb has higher resistance than the 60 W bulb, hence it dissipates more power and glows brighter.
How do I calculate monthly electricity cost from an appliance's power rating?+
Energy (kWh) = Power (kW) × time (h). For example, a 1.5 kW geyser used 2 hours daily for 30 days consumes 1.5 × 2 × 30 = 90 kWh. If the tariff is ₹6/kWh, cost = 90 × 6 = ₹540.
What is an Assertion-Reason MCQ and how do I solve it?+
You are given two statements: Assertion (A) and Reason (R). Decide independently if each is true or false. Then check if R correctly explains A. Four answer codes are provided: both true and R explains A; both true but R does not explain A; A true R false; A false R true.
Is the formula H = VIt the same as H = I²Rt?+
Yes, both are correct. Since V = IR, substituting gives H = (IR)It = I²Rt. Use H = VIt when voltage and current are given; use H = I²Rt when current and resistance are given. Both yield heat in joules.
Can I use a calculator in the CBSE Class 10 Science board exam?+
No. Calculators are not allowed. All numerical MCQs are designed to involve simple arithmetic. Practice mental math and approximations: for example, 230²/1500 ≈ 50000/1500 ≈ 33 Ω.
Where can I find more MCQs and instant doubt-solving for Electricity?+
CBSETUTOR.ai offers unlimited AI-generated MCQs, previous years' questions, and 24×7 photo-upload doubt-solving for CBSE Class 10 Science. One flat fee of ₹999/month covers all subjects and classes 6–12, with a 3-day free trial to start.

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