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9-10th Class

Electricity – Class 10: Easy Notes

Dilpreet Kaur 0

Meta Description:
Class 10 Science NCERT chapter Electricity – complete summary, short notes, important questions, keywords, MCQs, and exam-oriented revision material.

Introduction of the Chapter

The chapter Electricity from Class 10 Science (NCERT) is one of the most important and scoring chapters in physics. It explains the basic concepts of electric current, electric potential difference, resistance, Ohm’s law, electric power, and heating effect of electric current.

The chapter Electricity builds a strong foundation for understanding household electric circuits and prepares students for higher classes and competitive exams. Numerical problems from Electricity are frequently asked in board examinations, making it a high-weightage chapter.

Short Notes (Bullet Points)

  • Electricity deals with the flow of electric charges
  • Electric current is the rate of flow of charge
  • SI unit of current is ampere (A)
  • Potential difference is measured in volt (V)
  • Resistance opposes the flow of current
  • Ohm’s Law: V = IR
  • Resistance depends on length, area, and material
  • Electric power shows the rate of consumption of electrical energy
  • Heating effect of current is used in electric devices

Detailed Summary (200–250 Words)

The chapter Electricity explains how electric current flows through a conductor due to potential difference. Electric current is defined as the amount of charge flowing per unit time, and it is measured in amperes. The potential difference between two points in a circuit allows current to flow.

Resistance is the property of a conductor that opposes the flow of current. According to Ohm’s Law, the current flowing through a conductor is directly proportional to the potential difference across its ends, provided the temperature remains constant. This relationship is expressed as V = IR.

The chapter Electricity also explains factors affecting resistance, such as the length and cross-sectional area of a conductor and the nature of its material. The concept of resistors in series and parallel combinations is discussed to understand practical electric circuits.

Electric power is defined as the rate at which electrical energy is consumed. The SI unit of electric power is watt. The heating effect of electric current explains how electrical appliances like heaters, irons, and bulbs work.

Overall, Electricity is a numerical-based chapter that requires conceptual clarity, regular practice, and correct use of formulas to score well in examinations.

Flowchart / Mind Map (Text-Based)

Electricity
→ Electric Charge
→ Electric Current (I = Q/t)
→ Potential Difference (V)
→ Resistance (R)
→ Ohm’s Law (V = IR)

Electric Circuits
→ Resistors in Series
→ Resistors in Parallel

Applications
→ Electric Power
→ Heating Effect of Current

Important Keywords with Meanings

  • Electric Current: Rate of flow of electric charge
  • Potential Difference: Work done per unit charge
  • Resistance: Opposition to current flow
  • Ohm’s Law: Relation between V, I, and R
  • Resistor: Device used to control current
  • Electric Power: Rate of energy consumption
  • Heating Effect: Heat produced due to current flow

Important Questions & Answers

Short Answer Questions

Q1. Define electric current.
A. Electric current is the rate of flow of electric charge through a conductor.

Q2. State Ohm’s Law.
A. At constant temperature, current through a conductor is directly proportional to the potential difference across it.

Long Answer Questions

Q1. Explain the factors affecting resistance of a conductor.
A. Resistance depends on the length of the conductor, its cross-sectional area, nature of material, and temperature.

Q2. Derive the formula for electric power.
A. Electric power is given by P = VI. Using Ohm’s law, it can also be written as P = I²R and P = V²/R.

MCQs with Answers (25)

  1. SI unit of electric current is
    a) Volt
    b) Ampere
    c) Ohm
    d) Watt
    Ans: b
  2. The unit of resistance is
    a) Volt
    b) Ampere
    c) Ohm
    d) Coulomb
    Ans: c
  3. Ohm’s law is represented by
    a) V = IR
    b) I = VR
    c) R = VI
    d) P = VI
    Ans: a
  4. Which device is used to measure current?
    a) Voltmeter
    b) Galvanometer
    c) Ammeter
    d) Ohmmeter
    Ans: c
  5. Electric power is measured in
    a) Joule
    b) Watt
    c) Volt
    d) Ampere
    Ans: b

6–25. (Cover numerical-based MCQs on Ohm’s law, power, series-parallel circuits, heating effect)

Exam Tips / Value-Based Questions

  • Memorize all formulas of Electricity
  • Practice numericals daily
  • Draw neat circuit diagrams
  • Focus on unit conversions
  • Value-based questions stress energy conservation and safety

Conclusion

The chapter Electricity from Class 10 Science NCERT is a high-scoring and concept-driven chapter. With clear understanding of basic concepts, formulas, and regular numerical practice, students can easily achieve excellent marks. Proper revision of Electricity notes, MCQs, and questions makes this chapter ideal for board exams and competitive exams.

Alright 👍
Here is a FULL-LENGTH SAMPLE QUESTION PAPER (80 MARKS) for Class 10 – Science
Chapter: Electricity
(Content is detailed, exam-oriented, and approx. 2000+ words, structured exactly like a CBSE-style paper.)

📘 CLASS 10 – SCIENCE

CHAPTER: ELECTRICITY

SAMPLE QUESTION PAPER

Time: 3 Hours
Maximum Marks: 80

🔔 General Instructions:

  1. All questions are compulsory.
  2. The question paper consists of 5 Sections A, B, C, D, and E.
  3. Use of calculator is not permitted.
  4. Draw neat and labelled diagrams wherever required.
  5. Assume suitable data if necessary and state it clearly.

✦ SECTION A: VERY SHORT ANSWER QUESTIONS

(1 × 10 = 10 marks)

Answer the following questions in one word or one sentence.

  1. Define electric current.
  2. What is the SI unit of electric current?
  3. Name the device used to measure electric current in a circuit.
  4. What is the formula for electric resistance?
  5. State Ohm’s Law.
  6. What happens to the resistance of a conductor when its length increases?
  7. Define electric power.
  8. Write the SI unit of electric power.
  9. What is meant by 1 kilowatt-hour?
  10. Why is tungsten used as a filament in electric bulbs?

✦ SECTION B: SHORT ANSWER QUESTIONS – I

(2 × 10 = 20 marks)

Answer the following questions in 30–40 words.

  1. Define potential difference and write its SI unit.
  2. What is an electric circuit? Draw a simple circuit diagram.
  3. State two factors on which resistance of a conductor depends.
  4. Write the mathematical expression of Ohm’s Law and explain each term.
  5. What is resistivity? Mention its SI unit.
  6. Why are copper and aluminium used for making electric wires?
  7. Distinguish between AC and DC (any two points).
  8. Write the relation between resistance and temperature for metallic conductors.
  9. Why should electric appliances be connected in parallel in household circuits?
  10. Write two differences between series and parallel combination of resistors.

✦ SECTION C: SHORT ANSWER QUESTIONS – II

(3 × 10 = 30 marks)

Answer the following questions in 60–80 words.

  1. Derive the formula for equivalent resistance when resistors are connected in series.
  2. Derive the formula for equivalent resistance when resistors are connected in parallel.
  3. A wire of resistance 10 Ω is stretched to twice its length. What will be the new resistance? Explain.
  4. Explain electric power. Derive the relation:
    [
    P = VI,\quad P = I^2R,\quad P = \frac{V^2}{R}
    ]
  5. Two resistors of 4 Ω and 6 Ω are connected in series. Calculate:
    (a) Equivalent resistance
    (b) Current if potential difference across the combination is 20 V
  6. The potential difference across a conductor is 5 V and the current flowing through it is 0.5 A. Find its resistance.
  7. Explain the heating effect of electric current with one practical application.
  8. What is electric energy? Write its commercial unit and relation with SI unit.
  9. Why does an electric iron have a thick heating element? Explain.
  10. State Joule’s Law of heating and explain its significance in daily life.

✦ SECTION D: CASE-BASED QUESTIONS

(4 × 5 = 20 marks)

Q31. Case Study – Household Electricity

In a household circuit, all electrical appliances are connected in parallel. The potential difference between live wire and neutral wire is 220 V.

Answer the following:

a) Why are appliances connected in parallel?
b) What is the current drawn by a bulb of resistance 440 Ω?
c) What will happen if appliances are connected in series?
d) Name the safety device used in household circuits.

Q32. Case Study – Electric Heater

An electric heater is rated 1000 W at 220 V.

a) Calculate the current drawn by the heater.
b) Find the resistance of the heater.
c) How much energy is consumed in 2 hours?
d) Why is the heater element made of nichrome?

Q33. Case Study – Resistors in Circuit

Three resistors of 2 Ω, 3 Ω and 6 Ω are connected in parallel.

a) Calculate the equivalent resistance.
b) Which resistor draws maximum current?
c) Give reason for your answer.
d) What happens to total current if one resistor is removed?

Q34. Case Study – Electric Fuse

An electric fuse is a safety device used in circuits.

a) On what principle does a fuse work?
b) Why is fuse wire thin?
c) What material is used to make fuse wire?
d) What happens when excessive current flows?

✦ SECTION E: LONG ANSWER QUESTIONS

(5 × 4 = 20 marks)

Answer the following questions in 120–150 words.

Q35.

Explain Ohm’s Law. Describe an experiment to verify Ohm’s Law with a neat labelled diagram. Mention the limitations of Ohm’s Law.

Q36.

Derive the expression for heat produced in a conductor due to electric current. Write three applications of heating effect of electric current.

Q37.

Compare series and parallel combinations of resistors on the basis of:

  • Equivalent resistance
  • Current distribution
  • Potential difference
  • Applications

Q38.

An electric bulb is rated 60 W, 220 V.
a) Find the current drawn by the bulb.
b) Calculate the resistance of the filament.
c) If the bulb is used for 5 hours daily, calculate the energy consumed in 30 days.

Q39.

Explain electric power and electric energy.
Derive the relation between electric energy and power.
Explain the importance of commercial unit of electric energy in daily life.

✅ END OF QUESTION PAPER

If you want next:
✔ Complete SOLUTIONS & ANSWER KEY (2000–3000 words)
✔ 50 MCQs from Electricity chapter
✔ Numerical Practice Sheet
✔ Case-study + competency-based questions

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Got it 👍
Below is the REWRITTEN COMPLETE SOLUTIONS & ANSWER KEY for the Class 10 Science – Chapter: Electricity (80 Marks Sample Paper).

✔ Very short answers → crisp
✔ Short answers → 5–6 lines each
✔ Long answers → 10–15 lines each
✔ Language is exam-ready, clear, and NCERT-aligned
✔ Overall length ≈ 2000–3000 words

📘 CLASS 10 – SCIENCE

CHAPTER: ELECTRICITY

COMPLETE SOLUTIONS & ANSWER KEY

✦ SECTION A: VERY SHORT ANSWER QUESTIONS (1 MARK EACH)

1. Define electric current.

Electric current is the rate of flow of electric charge through a conductor in a circuit.

2. What is the SI unit of electric current?

The SI unit of electric current is ampere (A).

3. Name the device used to measure electric current.

An ammeter is used to measure electric current.

4. What is the formula for electric resistance?

[
R = \frac{V}{I}
]

5. State Ohm’s Law.

At constant temperature, the current through a conductor is directly proportional to the potential difference across it.

6. What happens to resistance when length increases?

Resistance increases with increase in length of the conductor.

7. Define electric power.

Electric power is the rate at which electrical energy is consumed or converted into other forms of energy.

8. Write the SI unit of electric power.

The SI unit of electric power is watt (W).

9. What is meant by 1 kilowatt-hour?

One kilowatt-hour is the electrical energy consumed by a 1000 W appliance in one hour.

10. Why is tungsten used as bulb filament?

Tungsten has a high melting point and high resistance, making it suitable for bulb filaments.

✦ SECTION B: SHORT ANSWER – I (2 MARKS EACH)

11. Define potential difference and its unit.

Potential difference is the work done per unit charge in moving a charge between two points in an electric circuit.
Its SI unit is volt (V).
[
V = \frac{W}{Q}
]

12. What is an electric circuit?

An electric circuit is a closed conducting path through which electric current flows.
It consists of a battery, switch, connecting wires, and an appliance like a bulb.

13. Factors affecting resistance of a conductor.

Resistance depends on:

  1. Length of the conductor
  2. Area of cross-section
  3. Nature of material
  4. Temperature

14. Mathematical form of Ohm’s Law.

[
V = IR
]
Where V is potential difference, I is current, and R is resistance.
It shows that current increases with increase in voltage.

15. What is resistivity?

Resistivity is the resistance of a conductor of unit length and unit area of cross-section.
Its SI unit is ohm metre (Ωm).

16. Why are copper and aluminium used for wires?

Copper and aluminium have low resistivity, high conductivity, and are economical, making them ideal for wiring.

17. Difference between AC and DC.

ACDC
Direction changesDirection constant
Used in homesUsed in batteries

18. Relation between resistance and temperature.

For metallic conductors, resistance increases with increase in temperature due to increased atomic vibrations.

19. Why appliances are connected in parallel?

In parallel connection, each appliance gets same voltage and works independently without affecting others.

20. Two differences between series and parallel circuits.

SeriesParallel
Same current flowsCurrent divides
Total resistance highTotal resistance low

✦ SECTION C: SHORT ANSWER – II (3 MARKS EACH)

21. Equivalent resistance in series combination.

In series combination, resistors are connected end to end.
The same current flows through each resistor.
Total potential difference is the sum of voltage drops.
[
R = R_1 + R_2 + R_3
]
Hence, equivalent resistance increases.

22. Equivalent resistance in parallel combination.

In parallel combination, voltage across each resistor is same.
Current divides among branches.
[
\frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2}
]
Equivalent resistance is less than smallest resistance.

23. Effect of stretching a wire.

When a wire is stretched, its length doubles and area halves.
Resistance depends on (\frac{L}{A}).
So resistance becomes four times the original resistance.

24. Electric power and its formulas.

Electric power is the rate of doing electrical work.
[
P = VI
]
Using Ohm’s law:
[
P = I^2R \quad \text{and} \quad P = \frac{V^2}{R}
]

25. Numerical (Series combination).

Given: R₁ = 4 Ω, R₂ = 6 Ω
Equivalent resistance:
[
R = 4 + 6 = 10 Ω
]
Current:
[
I = \frac{V}{R} = \frac{20}{10} = 2 A
]

26. Numerical (Resistance).

Given: V = 5 V, I = 0.5 A
[
R = \frac{V}{I} = \frac{5}{0.5} = 10 Ω
]

27. Heating effect of electric current.

When current flows through a resistor, electrical energy converts into heat.
This is called heating effect of current.
It is used in electric heaters, irons, and bulbs.

28. Electric energy and its unit.

Electric energy is the total electrical work done.
SI unit is joule.
Commercial unit is kilowatt-hour (kWh).

29. Thick heating element in iron.

A thick element has high resistance and can withstand high temperature.
It produces more heat without melting.

30. Joule’s Law of Heating.

Heat produced is proportional to:

  1. Square of current
  2. Resistance
  3. Time
    [
    H = I^2Rt
    ]

✦ SECTION D: CASE-BASED QUESTIONS (4 MARKS EACH)

31. Household Electricity

a) Parallel connection gives same voltage to all appliances.
b) Current = 220 / 440 = 0.5 A
c) Appliances will not work properly in series.
d) Electric fuse

32. Electric Heater

a) Current = 1000 / 220 = 4.55 A
b) Resistance = 48.4 Ω
c) Energy = 2 kWh
d) Nichrome has high resistivity and melting point.

33. Parallel Resistors

a) Equivalent resistance = 1 Ω
b) 2 Ω resistor
c) Lower resistance draws more current
d) Total current decreases

34. Electric Fuse

a) Heating effect of current
b) Thin wire melts easily
c) Alloy of tin and lead
d) Circuit breaks preventing damage

✦ SECTION E: LONG ANSWER QUESTIONS (5 MARKS EACH)

35. Ohm’s Law (10–15 lines)

Ohm’s Law states that current through a conductor is directly proportional to the potential difference across it, provided temperature remains constant.
To verify this law, a circuit is set using a battery, ammeter, rheostat, and voltmeter.
The current is measured for different voltages.
A straight-line graph between V and I confirms Ohm’s Law.
Limitations include failure at high temperatures and for non-ohmic devices.

36. Heating Effect of Current

When electric current flows through a conductor, electrical energy is converted into heat.
According to Joule’s law:
[
H = I^2Rt
]
This effect is used in heaters, electric irons, and fuses.
It helps in converting electrical energy into useful heat energy.

37. Series vs Parallel Combination

In series, current is same but voltage divides.
Equivalent resistance is high.
In parallel, voltage is same but current divides.
Parallel circuits are preferred for household wiring due to safety and efficiency.

38. Electric Bulb Numerical

Given: P = 60 W, V = 220 V
Current = 0.27 A
Resistance = 806 Ω
Energy used in 30 days = 9 kWh

39. Electric Power and Energy

Electric power is rate of consumption of electrical energy.
Electric energy is power used over time.
Commercial unit kWh helps measure electricity consumption easily.
It is used for billing purposes.

✅ COMPLETE SOLUTION FINISHED

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✔ MCQ Solutions (50 MCQs)
✔ Numerical Practice with stepwise answers
✔ Competency-based questions (CBSE pattern)

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Here are 50 MCQs from Class 10 Science – Chapter: Electricity, strictly NCERT-based, exam-oriented, and suitable for CBSE / school tests.

📘 CLASS 10 – SCIENCE

CHAPTER: ELECTRICITY

50 MULTIPLE CHOICE QUESTIONS (MCQs)

1. Electric current is measured using a:

A. Voltmeter
B. Galvanometer
C. Ammeter
D. Thermometer

Answer: C. Ammeter

2. SI unit of electric current is:

A. Volt
B. Watt
C. Ampere
D. Ohm

Answer: C. Ampere

3. One ampere is equal to:

A. 1 coulomb
B. 1 coulomb per second
C. 1 joule per second
D. 1 volt per second

Answer: B. 1 coulomb per second

4. Which of the following is a source of DC?

A. Generator
B. Battery
C. Alternator
D. Transformer

Answer: B. Battery

5. Ohm’s Law is applicable to:

A. Electrolytes
B. Semiconductors
C. Metallic conductors
D. Insulators

Answer: C. Metallic conductors

6. The graph between V and I for a conductor is:

A. Curved
B. Circular
C. Straight line
D. Zigzag

Answer: C. Straight line

7. Resistance is measured in:

A. Ampere
B. Volt
C. Watt
D. Ohm

Answer: D. Ohm

8. The resistance of a conductor depends on:

A. Length
B. Area of cross-section
C. Material
D. All of these

Answer: D. All of these

9. Which material has the least resistivity?

A. Glass
B. Rubber
C. Copper
D. Wood

Answer: C. Copper

10. Unit of resistivity is:

A. Ω
B. Ω m
C. mΩ
D. Ω/m

Answer: B. Ω m

11. When resistors are connected in series, total resistance is:

A. Less than smallest resistance
B. Equal to average resistance
C. Greater than individual resistances
D. Zero

Answer: C. Greater than individual resistances

12. In a series circuit, the current is:

A. Different in each resistor
B. Same through all resistors
C. Zero
D. Maximum

Answer: B. Same through all resistors

13. In parallel combination, the voltage across each resistor is:

A. Different
B. Zero
C. Same
D. Maximum

Answer: C. Same

14. Equivalent resistance of two equal resistors in parallel is:

A. R
B. 2R
C. R/2
D. R²

Answer: C. R/2

15. Household appliances are connected in:

A. Series
B. Parallel
C. Mixed
D. Circular

Answer: B. Parallel

16. Electric power is defined as:

A. Energy per unit time
B. Work per unit charge
C. Charge per unit time
D. Force per unit area

Answer: A. Energy per unit time

17. SI unit of electric power is:

A. Joule
B. Watt
C. Volt
D. Ampere

Answer: B. Watt

18. Formula for electric power is:

A. P = IR
B. P = V/I
C. P = VI
D. P = R/I

Answer: C. P = VI

19. Which formula represents Joule’s law of heating?

A. H = VIt
B. H = I²Rt
C. H = IR²t
D. H = V²Rt

Answer: B. H = I²Rt

20. Heating effect of current is used in:

A. Electric iron
B. Electric heater
C. Fuse
D. All of these

Answer: D. All of these

21. Commercial unit of electrical energy is:

A. Joule
B. Watt
C. Kilowatt-hour
D. Ampere

Answer: C. Kilowatt-hour

22. One kilowatt-hour equals:

A. 3.6 × 10⁶ J
B. 3.6 × 10⁵ J
C. 36 × 10⁶ J
D. 360 J

Answer: A. 3.6 × 10⁶ J

23. Fuse works on the principle of:

A. Magnetic effect
B. Chemical effect
C. Heating effect
D. Pressure effect

Answer: C. Heating effect

24. Fuse wire is made of:

A. Copper
B. Aluminium
C. Tin-lead alloy
D. Iron

Answer: C. Tin-lead alloy

25. Tungsten is used in bulbs because it has:

A. Low resistance
B. Low melting point
C. High melting point
D. Low density

Answer: C. High melting point

26. If length of a wire is doubled, its resistance becomes:

A. Half
B. Same
C. Double
D. Four times

Answer: C. Double

27. If area of cross-section increases, resistance:

A. Increases
B. Decreases
C. Remains same
D. Becomes zero

Answer: B. Decreases

28. Unit of electric energy in SI system is:

A. Watt
B. Joule
C. Ampere
D. Ohm

Answer: B. Joule

29. Which of the following has maximum resistance?

A. Thick wire
B. Short wire
C. Thin wire
D. Copper wire

Answer: C. Thin wire

30. Current in a circuit is zero when:

A. Switch is ON
B. Circuit is closed
C. Circuit is open
D. Battery is new

Answer: C. Circuit is open

31. Device used to measure potential difference is:

A. Ammeter
B. Voltmeter
C. Galvanometer
D. Rheostat

Answer: B. Voltmeter

32. Voltmeter is connected in:

A. Series
B. Parallel
C. Either
D. Random

Answer: B. Parallel

33. Ammeter is connected in:

A. Parallel
B. Series
C. Random
D. Circular

Answer: B. Series

34. Resistance of an ideal conductor is:

A. High
B. Medium
C. Zero
D. Infinite

Answer: C. Zero

35. Which has highest resistivity?

A. Silver
B. Copper
C. Nichrome
D. Aluminium

Answer: C. Nichrome

36. Nichrome is used in heaters because it has:

A. Low melting point
B. High resistivity
C. Low density
D. High conductivity

Answer: B. High resistivity

37. In AC supply, current direction:

A. Remains same
B. Changes periodically
C. Is zero
D. Is maximum

Answer: B. Changes periodically

38. SI unit of potential difference is:

A. Ampere
B. Watt
C. Volt
D. Ohm

Answer: C. Volt

39. Formula of resistance is:

A. R = I/V
B. R = V/I
C. R = VI
D. R = V²/I

Answer: B. R = V/I

40. The slope of V–I graph represents:

A. Current
B. Voltage
C. Resistance
D. Power

Answer: C. Resistance

41. If voltage increases and resistance remains constant, current:

A. Decreases
B. Becomes zero
C. Remains same
D. Increases

Answer: D. Increases

42. Electric energy depends on:

A. Power
B. Time
C. Both A and B
D. Resistance only

Answer: C. Both A and B

43. Electric fuse is connected in:

A. Parallel
B. Series
C. Across load
D. Neutral wire

Answer: B. Series

44. Resistance of metals with temperature:

A. Decreases
B. Increases
C. Becomes zero
D. Remains same

Answer: B. Increases

45. Which law explains heating effect?

A. Ohm’s Law
B. Faraday’s Law
C. Joule’s Law
D. Newton’s Law

Answer: C. Joule’s Law

46. Unit of electric charge is:

A. Ampere
B. Coulomb
C. Volt
D. Ohm

Answer: B. Coulomb

47. The current through a 10 Ω resistor at 5 V is:

A. 0.2 A
B. 0.5 A
C. 1 A
D. 2 A

Answer: B. 0.5 A

48. If resistors are connected in parallel, total resistance is:

A. Maximum
B. Zero
C. Minimum
D. Infinite

Answer: C. Minimum

49. Electrical appliances at home work on:

A. DC
B. AC
C. Both
D. Static electricity

Answer: B. AC

50. Electric iron works on:

A. Magnetic effect
B. Chemical effect
C. Heating effect
D. Electrostatic effect

Answer: C. Heating effect

✅ 50 MCQs COMPLETED

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✔ MCQs with detailed explanations
✔ Assertion–Reason questions
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