State Ohm's Law and write its formula.

Ohm's Law states: At constant temperature, the current flowing through a conductor is directly proportional to the potential difference across it. Formula: V = IR, where V = potential difference (volts), I = current (amperes), R = resistance (ohms).

What factors affect the resistance of a conductor?

Resistance depends on: (1) Length — longer conductor has more resistance (R ∝ L); (2) Cross-sectional area — thicker conductor has less resistance (R ∝ 1/A); (3) Material/Resistivity — different materials have different resistivity (ρ); (4) Temperature — resistance generally increases with temperature. Formula: R = ρL/A.

What is the difference between series and parallel circuits?

In series: resistors are connected end-to-end; same current flows through all; total resistance R = R₁+R₂+R₃ (always more than any single resistance). In parallel: resistors share same terminals; same voltage across all; 1/R = 1/R₁+1/R₂+1/R₃ (total resistance less than any single resistance). Household appliances use parallel connections.

Ohm's Law and Resistance

Electricity • Class 10 Science • NCERT • CBSE

Ohm's Law states that the current (I) flowing through a conductor is directly proportional to the potential difference (V) across it, at constant temperature: V = IR. Resistance (R) is measured in ohms (Ω) and depends on the material, length, and cross-sectional area of the conductor.

Key Formulas

V = IR (Ohm's Law)
R = ρL/A (Resistance formula)
R_series = R₁ + R₂ + R₃
1/R_parallel = 1/R₁ + 1/R₂ + 1/R₃
P = VI = I²R = V²/R (Electric Power)
H = I²Rt (Joule's Law of Heating)

Frequently Asked Questions

State Ohm's Law and write its formula.: Ohm's Law states: At constant temperature, the current flowing through a conductor is directly proportional to the potential difference across it. Formula: V = IR, where V = potential difference (volts), I = current (amperes), R = resistance (ohms).
What factors affect the resistance of a conductor?: Resistance depends on: (1) Length — longer conductor has more resistance (R ∝ L); (2) Cross-sectional area — thicker conductor has less resistance (R ∝ 1/A); (3) Material/Resistivity — different materials have different resistivity (ρ); (4) Temperature — resistance generally increases with temperature. Formula: R = ρL/A.
What is the difference between series and parallel circuits?: In series: resistors are connected end-to-end; same current flows through all; total resistance R = R₁+R₂+R₃ (always more than any single resistance). In parallel: resistors share same terminals; same voltage across all; 1/R = 1/R₁+1/R₂+1/R₃ (total resistance less than any single resistance). Household appliances use parallel connections.

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