Karnataka Board Class 12 Physics — Flashcards for Quick Revision

A: Given: q₁ = +3 μC = 3×10⁻⁶ C, q₂ = -5 μC = -5×10⁻⁶ C, r = 30 cm = 0.3 m Formula: F = k|q₁q₂|/r² Step 1: F = (9×10⁹ × 3×10⁻⁶ × 5×10⁻⁶)/(0.3)² Step 2: F = (135×10⁻³)/(0.09) = 1.5 N Since charges are opp

A: This happens due to electrostatic charging by friction. When synthetic clothes rub against skin, electrons transfer between surfaces, creating opposite charges. The attractive force between these oppo

A: Coulomb's Law: The electrostatic force between two point charges is directly proportional to the product of charges and inversely proportional to the square of distance between them. Mathematical form

A: The laws of reflection are: 1. The angle of incidence equals the angle of reflection (∠i = ∠r) 2. The incident ray, reflected ray, and normal to the surface at the point of incidence all lie in the sa

A: Snell's law states that the ratio of sine of angle of incidence to sine of angle of refraction is constant for a given pair of media. Mathematically: sin i / sin r = n₂₁ (constant) Where n₂₁ is the

A: Mirror equation: 1/v + 1/u = 1/f Where: - u = object distance from pole - v = image distance from pole - f = focal length of mirror This equation relates object distance, image distance, and focal l

A: Electrostatic potential energy is the energy stored in a charge due to its position in an electric field. It equals the work done by an external force in bringing the charge from infinity to that poin

A: Electrostatic potential (V) at a point is the work done per unit positive charge in bringing a test charge from infinity to that point. V = W/q. SI unit is volt (V), where 1 volt = 1 joule/coulomb. No

A: V(r) = (1/4πε₀) × (Q/r), where V(r) is potential at distance r from point charge Q, ε₀ is permittivity of free space (8.85 × 10⁻¹² C²N⁻¹m⁻²), and r is distance from charge. For Q > 0, V > 0; for Q < 0