Ohm's law
Ohm's law states that at constant temperature, the current through a conductor is directly proportional to the potential difference across it.
Practice This ConceptMain explanation
Teacher explanation
For a given conductor kept at the same temperature, increasing voltage increases current in the same proportion. This relation is one of the most important ideas in circuit numericals and graphs. It is written as V = IR.
Example
If a resistor has 2 A current at 6 V, then its resistance is 3 ohm.
Simple analogy
V pushes, I flows, R resists.
Common confusion
Students sometimes use the formula without keeping temperature constant or swap the quantities wrongly.
Exam tip
Always check that the question says constant temperature before using the law directly.
Study the ohm's law diagram carefully
Use the labelled diagram to keep ohm's law clear in short answers and revision.
What this diagram makes clear
This diagram keeps the labels and direction of ohm's law in the right order.
Where this helps in exams
Use this for labelled diagram work and short exam answers on ohm's law.
Revision cue
Revise ohm's law through the labels before writing the answer.
Answer writing and exam use
1-mark use
Write the exact meaning of ohm's law in one clean line.
2-mark use
Define ohm's law and add one example or condition.
3-mark use
Explain ohm's law, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
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