Electric Current Through Conductors — Important Questions

Current is directly proportional to voltage, Current is inversely proportional to resistance, Voltage is directly proportional to resistance, V = IR for ohmic conductors

Ohm's law states V = IR, which means: (1) V ∝ I (when R is constant), (2) I ∝ 1/R (when V is constant), (3) V ∝ R (when I is constant). Resistance is a property of the material and doesn't depend on current for ohmic conductors.

10 Ω

For resistors in series, the equivalent resistance is the sum of individual resistances: Rs = R₁ + R₂ = 4 Ω + 6 Ω = 10 Ω. In series combination, the same current flows through all resistors.

2.4 Ω

For resistors in parallel: 1/Rp = 1/R₁ + 1/R₂ = 1/4 + 1/6 = 3/12 + 2/12 = 5/12. Therefore, Rp = 12/5 = 2.4 Ω. In parallel combination, the same voltage appears across all resistors.

P = VI, P = I²R, P = V²/R

Power dissipated in a resistor can be calculated using three equivalent formulas: P = VI (basic power formula), P = I²R (when current is known), and P = V²/R (when voltage is known). These are derived from P = VI and Ohm's law V = IR.