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Radioactivity

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Audio Podcast Quiz 1:   Fullscreen Mode Quiz 2:   Fullscreen Mode Other note 1 source Other note 2 source  5.2.1 Detection of radioactivity ## Radioactivity Detection Radioactivity is the process of releasing radiation from an unstable atomic nucleus. We are all exposed to radiation from various sources every day. Let's discuss some important things about radioactivity: ## Background Radiation Sources Background radiation comes from a variety of sources, both natural and artificial: - Cosmic rays from the sun - Radon gas in the air - Radon-containing granite rocks - Potassium-40 in food - Medical procedures that use radioisotopes - Nuclear power plants and the rest of the nuclear bomb tests ## Ionization Effect Radiation can cause ionization, which is the process of releasing electrons from atoms or molecules. This can be evidenced by: Electroscope Experiments: - When a fire or radium source is brought close to a charged electroscope, the charge is los...
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Fractions, Percentages and Standard Form

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Quiz 1:   Fullscreen Mode Fractions, Percentages and Standard Form - Complete Guide 📐 FRACTIONS, PERCENTAGES AND STANDARD FORM 📊 Complete Theory and Formulas for Cambridge IGCSE Grade 9 Mathematics 1️⃣ EQUIVALENT FRACTIONS 📌 Definition Equivalent fractions are fractions that represent the same value but have different numerators and denominators. They are created by multiplying or dividing both the numerator and denominator by the same non-zero number. Key Formula: a b = a × k b × k where k is any non-zero number 1 2 = 2 4 = 3 6 = 4 8 🔍 Cross Multiplication Method To find a missing value in equivalent fractions, use cross multiplication: If a b = c d Then: a × d = b × c Example: Find x if 2 5 ...
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Quadratic Equation and Graphs

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Quadratic Functions and Their Graphs A quadratic function is a polynomial function of degree 2, typically written in the form: $$f(x) = ax^2 + bx + c$$ where a, b, and c are constants and a ≠ 0. Important Properties of Quadratic Function Graphs Y-Intercept: The point where the parabola crosses the y-axis (0, c) X-Intercepts: Also known as zeros, roots, or solutions - points where the parabola crosses the x-axis Vertex: The highest or lowest point of the parabola Axis of Symmetry: A vertical line that passes through the vertex, dividing the parabola into two symmetrical halves Forms of Quadratic Functions 1. Standard Form $$f(x) = ax^2 + bx + c$$ To find the axis of symmetry: $$x = -\frac{b}{2a}$$ 2. Vertex Form $$f(x) = a(x - h)^2 + k$$ Where (h, k) is the vertex of the parabola Characteristics of Parabolas If a > 0, the parabola opens upward (U-shaped) If a The larger the absolute value of a, the narrower the parabola...
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