Electricity — Karnataka (SSLC) Class 10 Science Solutions (Free)

Ohm's law: V = IR, where voltage (V) is directly proportional to current (I) and resistance (R). Resistance is the opposition offered by a conductor to the flow of electric current. Unit: Ohm (Ω). A conductor has 1 Ω resistance if 1 A current flows when 1 V is applied.

Resistivity (ρ) is the property of a material that determines its resistance; it's intrinsic to the material. Resistance (R) depends on resistivity, length, and area. Formula: R = ρL/A, where L = length, A = cross-sectional area. Unit of ρ: Ω⋅m. Materials with lower ρ are better conductors.

Step 1: Given V = 10 V, R = 5 Ω Step 2: Using Ohm's law: V = IR Step 3: I = V/R = 10/5 = 2 A Step 4: Current flowing through the resistor is 2 amperes

Power (P) is the rate of energy consumption: P = VI = I²R = V²/R (watts). Energy (E) is total work done over time: E = Pt = VIt (joules or kWh). 1 unit of electricity = 1 kWh = 3.6 × 10⁶ J. A 100 W bulb uses 0.1 kW; run 10 h = 1 kWh energy.

Series: components connected one after another. Current same everywhere, voltage divides, Rₜ = R₁+R₂+R₃. Parallel: components connected across same points. Voltage same, current divides, 1/Rₜ = 1/R₁+1/R₂+1/R₃. Series used for switches; parallel for home wiring (independent control).