Current Electricity — Maharashtra (SSC) Class 9 Science Solutions (Free)
Free step-by-step Maharashtra (SSC) Class 9 Science solutions for "Current Electricity" — important questions with detailed answers, download PDF for board exam preparation.
TL;DR: Free step-by-step Maharashtra (SSC) Class 9 Science solutions for "Current Electricity" — important questions with detailed answers, download PDF for…
By Syllab.in · Updated
Q1: State Ohm's law and write the formula. What is its SI unit?
Ohm's law: The current through a conductor is directly proportional to the potential difference across it, provided temperature remains constant. Formula: V = IR, or I = V/R. SI unit of resistance (R): Ohm (Ω). 1 Ω = 1 V/A.
Q2: A potential difference of 12 V is applied across a 4 Ω resistor. Calculate the current.
Step 1: V = 12 V, R = 4 Ω
Step 2: Using V = IR, I = V/R = 12/4 = 3 A
Current = 3 A
Q3: Define electric current and its SI unit. What does 1 Ampere mean?
Electric current (I) is the rate of flow of electric charge. SI unit: Ampere (A). 1 Ampere = 1 Coulomb/second. It means 1 coulomb of charge flows through a cross-section per second. Current flows from positive terminal to negative terminal (conventional current).
Q4: Three resistances of 2 Ω, 3 Ω, and 5 Ω are connected in series. Find equivalent resistance.
For series connection: Rₜₒₜₐₗ = R₁ + R₂ + R₃
Step 1: R₁ = 2 Ω, R₂ = 3 Ω, R₃ = 5 Ω
Step 2: Rₜₒₜₐₗ = 2 + 3 + 5 = 10 Ω
Equivalent resistance = 10 Ω
Q5: Define resistance and write factors that affect it.
Resistance (R) is the opposition offered by a conductor to the flow of current. Factors: (1) Material of conductor (ρ = resistivity), (2) Length of conductor (R ∝ L), (3) Cross-sectional area (R ∝ 1/A), (4) Temperature (R increases with temperature for most metals).
Showing 5 of 7 questions — full solutions on the page.