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Electricity
High trendapprox. 7 marksSections C/D — Ohm's-law numericals and series–parallel network problems.
CBSE 2027 — dates, rules and official papers →Ask the tutor1Always state SI units (V, A, Ω, W, J) — boards routinely deduct for missing units in numericals.
Notesformulae · proofs · mind-map — one view
Learn the 8 conceptsteach yourself first, then practise each
Electric Current and Circuit1–4 marks
Use I = Q/t, the ammeter in series and the + to − direction of conventional current in a closed circuit.
Electric Potential and Potential Difference1–5 marks
Use V = W/Q (1 volt = 1 joule per coulomb) and place the voltmeter in parallel across the part measured.
Ohm's law V = IR1–3 marks
Bridge any two of V, I, R when the third is known.
Resistivity ρ and the factors resistance depends on (R = ρl/A)2–3 marks
Scale R with length, cross-section area and material, and compute ρ with its unit Ω m.
Resistors in series (R = R₁ + R₂ + …)2–3 marks
Collapse a chain into one equivalent resistor before applying Ohm's law.
Resistors in parallel (1/R = 1/R₁ + 1/R₂ + …)3–5 marks
Find equivalent resistance and branch currents.
Electrical power (P = VI = I²R = V²/R)2–3 marks
Pick the form that matches the two known quantities.
Joule's heating (H = I²Rt)2–3 marks
Compute heat produced by a current over time.
When you’re ready — practise or test the whole topic