516 marks

Current electricity

This chapter covers electric current, resistance, Ohm's law, Kirchhoff's laws, and their applications in circuits.

18 Topics

50h prep

5.3% subject weight

18 Topics

Electric current

2m1/10

📌 Key FormulaI = dQ/dt

Drift velocity

2m2/10

📌 Key Formulav_d = eEτ/m, I = nA e v_d

Ohm's law

2m1/10

📌 Key FormulaV = IR

Electrical resistance

2m1/10

📌 Key FormulaR = ρL/A

Resistances of different materials

2m1/10

📌 Key FormulaConductors, semiconductors, insulators have different resistivities.

V-l characteristics of Ohmic and non-ohmic conductors

2m2/10

📌 Key FormulaOhmic: linear V-I graph, non-ohmic: non-linear (e.g., diode).

Electrical energy and power

2m2/10

📌 Key FormulaE = P t = V I t = I²R t, P = V I = I²R = V²/R

Electrical resistivity

2m1/10

📌 Key Formulaρ = RA/L, depends on material and temperature.

Colour code for resistors

2m1/10

📌 Key FormulaColor bands indicate resistance value and tolerance.

Series and parallel combinations of resistors

2m2/10

📌 Key FormulaSeries: R_eq = R₁ + R₂ + ..., Parallel: 1/R_eq = 1/R₁ + 1/R₂ + ...

Temperature dependence of resistance

2m2/10

📌 Key FormulaR = R₀(1 + αΔT)

Electric Cell and its Internal resistance

2m2/10

📌 Key FormulaV = E - I r

Potential difference and emf of a cell

2m2/10

📌 Key FormulaEMF is the voltage when no current flows, PD is voltage when current flows.

A combination of cells in series and parallel

2m3/10

📌 Key FormulaSeries: E_eq = E₁ + E₂ + ..., r_eq = r₁ + r₂ + ... Parallel: For identical cells, E_eq = E, r_eq = r/n

Kirchhoff’s laws and their applications

2m4/10

📌 Key FormulaJunction law: Σ I_in = Σ I_out, Loop law: Σ ΔV = 0

Wheatstone bridge

2m3/10

📌 Key FormulaBalanced condition: P/Q = R/S

Metre Bridge

2m2/10

📌 Key FormulaApplication of Wheatstone bridge to measure unknown resistance.

Potentiometer - principle and its applications

2m3/10

📌 Key FormulaV ∝ l, used to measure emf, compare emfs, measure internal resistance.

516 marks

Current electricity

This chapter covers electric current, resistance, Ohm's law, Kirchhoff's laws, and their applications in circuits.

18 Topics

50h prep

5.3% subject weight

18 Topics

Electric current

2m1/10

📌 Key FormulaI = dQ/dt

Drift velocity

2m2/10

📌 Key Formulav_d = eEτ/m, I = nA e v_d

Ohm's law

2m1/10

📌 Key FormulaV = IR

Electrical resistance

2m1/10

📌 Key FormulaR = ρL/A

Resistances of different materials

2m1/10

📌 Key FormulaConductors, semiconductors, insulators have different resistivities.

V-l characteristics of Ohmic and non-ohmic conductors

2m2/10

📌 Key FormulaOhmic: linear V-I graph, non-ohmic: non-linear (e.g., diode).

Electrical energy and power

2m2/10

📌 Key FormulaE = P t = V I t = I²R t, P = V I = I²R = V²/R

Electrical resistivity

2m1/10

📌 Key Formulaρ = RA/L, depends on material and temperature.

Colour code for resistors

2m1/10

📌 Key FormulaColor bands indicate resistance value and tolerance.

Series and parallel combinations of resistors

2m2/10

📌 Key FormulaSeries: R_eq = R₁ + R₂ + ..., Parallel: 1/R_eq = 1/R₁ + 1/R₂ + ...

Temperature dependence of resistance

2m2/10

📌 Key FormulaR = R₀(1 + αΔT)

Electric Cell and its Internal resistance

2m2/10

📌 Key FormulaV = E - I r

Potential difference and emf of a cell

2m2/10

📌 Key FormulaEMF is the voltage when no current flows, PD is voltage when current flows.

A combination of cells in series and parallel

2m3/10

📌 Key FormulaSeries: E_eq = E₁ + E₂ + ..., r_eq = r₁ + r₂ + ... Parallel: For identical cells, E_eq = E, r_eq = r/n

Kirchhoff’s laws and their applications

2m4/10

📌 Key FormulaJunction law: Σ I_in = Σ I_out, Loop law: Σ ΔV = 0

Wheatstone bridge

2m3/10

📌 Key FormulaBalanced condition: P/Q = R/S

Metre Bridge

2m2/10

📌 Key FormulaApplication of Wheatstone bridge to measure unknown resistance.

Potentiometer - principle and its applications

2m3/10

📌 Key FormulaV ∝ l, used to measure emf, compare emfs, measure internal resistance.