Current Electricity Most Important Questions, Download PDF & Preparation Tips.
Current Electricity covers the steady flow of electric charges through conductors, including Ohm’s law, drift velocity, resistivity, and temperature effects. This page includes important 2-mark, 3-mark, and 5-mark questions, along with numericals, derivations, preparation tips.
Harmanpreet Kaur28 Sept, 2026
Mastering the 12th Physics Current Electricity important questions helps you score high marks in the board exam. Current Electricity bridges fundamental electrostatics with functional electric circuits. Question papers frequently test core definitions, circuit laws, and bridge balance conditions, so regular practice prepares you for both the short and long answer sections.
This guide highlights the 12th Physics Chapter 2 important questions to sharpen your problem-solving speed. You will review circuit laws, study step-by-step derivations, and solve resistive network problems, which builds exam confidence and improves accuracy. Follow the latest Tamil Nadu HSC 12th 2027 notification for board updates, and check the Tamil Nadu HSE 2nd year time table 2027 to plan your revision around the exam dates.
Tamil Nadu Current Electricity Overview
The table below gives a quick snapshot of Unit 2 and the resources on this page.
| Particulars | Details |
| Board | Directorate of Government Examinations (DGE), Tamil Nadu |
| Class | 12th (HSC / +2) |
| Subject | Physics |
| Unit | Unit 2: Current Electricity |
| Important 2 Mark Questions | 14 |
| Important 3 Mark Questions | 5 |
| Important 5 Mark Questions | 6 |
| Theory Marks (Physics) | 70 |
| Exam Duration | 3 hours |
12th Physics Unit 2 Current Electricity Important Questions
You can practise the most essential 12th Physics Unit 2 Current Electricity important questions below. The list covers core definitions, circuit analysis problems, and major derivations asked in board exams. The table shows how the questions are grouped so you can plan your revision.
| Question Type | Marks | Number of Questions | What to Expect |
| Very short answer | 2 | 14 | Definitions, laws, thermoelectric effects, and short notes |
| Short answer | 3 | 5 | Drift velocity, power, Seebeck effect, resistor networks, and Kirchhoff's rules |
| Long answer | 5 | 6 | Ohm's law, resistor networks, and bridge and potentiometer experiments |
Current Electricity Important 2 Mark Questions
These questions test your grasp of basic definitions and laws. Write the definition, the formula, and the SI unit in each answer to secure full marks.
| S.No. | Important 2 Mark Question |
| 1 | Why is current a scalar? |
| 2 | Define current density. |
| 3 | What are ohmic and non-ohmic devices? |
| 4 | Define electrical resistivity. |
| 5 | Define temperature coefficient of resistance. |
| 6 | Write a short note on superconductors. |
| 7 | What is electric power and electric energy? |
| 8 | State Kirchhoff's current rule. |
| 9 | State Kirchhoff's voltage rule. |
| 10 | State the principle of potentiometer. |
| 11 | State Joule's law of heating. |
| 12 | What is Seebeck effect? |
| 13 | What is Thomson effect? |
| 14 | What is Peltier effect? |
Current Electricity Important 3 Mark Questions
The 3 mark questions ask for distinctions, short derivations and explanations. Keep your answer to clear points, include the formula, and draw the circuit where needed.
| S.No. | Important 3 Mark Question |
| 1 | Distinguish between drift velocity and mobility. |
| 2 | Derive the expression for power P = VI in an electrical circuit. |
| 3 | State the applications of Seebeck effect. |
| 4 | Explain the equivalent resistance of a series and parallel resistor network. |
| 5 | State and explain Kirchhoff's rules. |
Current Electricity Important 5 Mark Questions
Five mark questions are long derivations and experiment-based answers. Draw a neat circuit diagram, define every symbol, show each step, and write the final formula clearly.
| S.No. | Important 5 Mark Question |
| 1 | Describe the microscopic model of current and obtain the general form of Ohm's law. |
| 2 | Explain the equivalent resistance of a series and parallel resistor network. |
| 3 | Explain the determination of the internal resistance of a cell using a voltmeter. |
| 4 | Obtain the condition for bridge balance in Wheatstone's bridge. |
| 5 | Explain the determination of unknown resistance using a meter bridge. |
| 6 | How are the emf of two cells compared using a potentiometer? |
Current Electricity Important Numerical Problems
Numericals in this unit are formula-based and quick to score once you practise. The table gives sample problems with answers so you can check your working. Write the formula, substitute with units, and state the final answer with its unit.
| S.No. | Numerical Problem | Answer |
| 1 | A current of 2 A flows through a wire for 10 s. Find the charge that passes through it. | 20 C |
| 2 | Resistors of 2 Ω, 3 Ω and 6 Ω are connected in series. Find the equivalent resistance. | 11 Ω |
| 3 | The same three resistors are connected in parallel. Find the equivalent resistance. | 1 Ω |
| 4 | A 10 Ω resistor carries a current of 5 A. Find the power dissipated and the heat produced in 2 minutes. | P = 250 W; H = 30,000 J |
| 5 | A cell of emf 1.5 V is connected to an external resistance of 4 Ω. The internal resistance of the cell is 1 Ω. Find the current and the terminal voltage. | I = 0.3 A; V = 1.2 V |
| 6 | In a balanced Wheatstone bridge, P = 10 Ω, Q = 20 Ω and R = 30 Ω. Find the unknown resistance S. | 60 Ω |
| 7 | In a meter bridge, the balancing length is 40 cm when a known resistance of 10 Ω is in the left gap. Find the unknown resistance. | 15 Ω |
| 8 | A wire of length 2 m and cross-section 1 mm² has a resistance of 0.034 Ω. Find its resistivity. | 1.7 × 10⁻⁸ Ω m |
Current Electricity Important Derivations
Derivations and experiment-based answers make up all of the 3 mark and 5 mark questions in this unit, so learn them step by step. The table lists each one with its marks and the main concept it relies on.
| S.No. | Derivation / Explanation | Marks | Key Concept Used |
| 1 | Expression for power P = VI | 3 | Work done in moving charge across a potential difference |
| 2 | Equivalent resistance of series and parallel networks | 3 and 5 | Same current in series, same voltage in parallel |
| 3 | Kirchhoff's current and voltage rules | 3 | Conservation of charge and energy |
| 4 | Microscopic model of current and Ohm's law | 5 | Drift velocity, relaxation time, and current density |
| 5 | Internal resistance of a cell using a voltmeter | 5 | Terminal voltage and the emf relation |
| 6 | Condition for bridge balance in Wheatstone's bridge | 5 | Kirchhoff's rules with zero galvanometer current |
| 7 | Unknown resistance using a meter bridge | 5 | Wheatstone bridge principle and balancing length |
| 8 | Comparison of emf of two cells using a potentiometer | 5 | Potential drop is proportional to wire length |
Tamil Nadu Class 12 Physics Unit 2 Current Electricity PDF Download
You can access the Tamil Nadu 12th Physics Current Electricity important questions in a printable format. The file allows easy offline revision and quick formula reference during revision sessions.
Current Electricity Most Important Questions
Download and practice with Most Important Questions.
How to Prepare Unit 2 Current Electricity for the 12th Physics Exam?
Systematic preparation ensures complete mastery over theoretical concepts and numerical problems. Follow these structured steps to revise the unit efficiently.
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Study basic concepts first. Review the microscopic model of Ohm's law, mobility, and internal resistance before attempting complex circuit problems. Check the Tamil Nadu HSC syllabus to confirm the topics.
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Master circuit laws. Practise applying Kirchhoff's rules to multi-loop circuits. Clear sign conventions prevent calculation mistakes.
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Practise core derivations. Write out the Wheatstone bridge condition and the potentiometer applications repeatedly, with neat circuit diagrams.
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Solve numerical problems. Work through standard TN 12th Physics Current Electricity questions to calculate equivalent resistance and power dissipation accurately.
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Attempt model papers and past papers. Solve the Tamil Nadu 12th Physics model papers and previous year question papers to see how the questions are asked.
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Conduct timed self-tests. Solve selected 12th Physics Current Electricity questions within a set time limit to improve speed. Read the Tamil Nadu Class 12 exam pattern to plan your time across the parts.
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Plan around the exam dates. Use the Tamil Nadu HSE 2nd year time table 2027 to set a revision schedule, and keep an eye on the Tamil Nadu HSC 12th 2027 notification for any official updates.
Current Electricity Most Important Questions FAQs
1. Which derivations carry the highest weight in Unit 2?
2. Why is Kirchhoff's loop rule called an energy conservation law?
3. What is the relation between drift velocity and electric current?
4. Which 5 mark questions are important in Current Electricity?
5. How can I score full marks in Current Electricity numericals?
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