Class 9 Vinayak Study Junction Beawar

Class 9 Chapter 2 Is Matter Around Us Pure?                                                                                                                                          *   **What is a pure substance?**      A pure substance is a single form of matter that consists of only one type of particle, and all its constituent particles are the same in their chemical nature. *   **What is a mixture?**      A mixture contains more than one kind of pure substance mixed together in any proportion without reacting chemically. *   **What is a solution?**      A solution is a h...

 Chapter 3   Atoms and Molecules                                                                                                                                **History of the Atom** *   **Q: Which ancient Indian philosopher named the smallest indivisible particles of matter "Parmanu"?**      **A:** Maharishi Kanad. *   **Q: Which ancient Greek philosophers suggested the name "atoms" (meaning indivisible) for the smallest particles of matter?**      **A:** Democritus and Leucippus. **Laws of Chemical Combination** *   **Q: Who laid the foundation of chemical sciences by establishing two important l...

 Chapter 4      Structure of the Atom                                                      **Q: Who identified the sub-atomic particle known as the electron?** A: The electron was identified by J.J. Thomson. **Q: Who discovered canal rays and when?** A: E. Goldstein discovered canal rays in 1886. **Q: What are canal rays?** A: Canal rays are positively charged radiations found in a gas discharge, which ultimately led to the discovery of the proton. **Q: Who was the first scientist to propose a model for the structure of an atom?** A: J.J. Thomson was the first to propose a model for the structure of an atom. **Q: What real-world objects did Thomson use to describe his atomic model?** A: Thomson compared his atomic model to a Christmas pudding and a watermelon. **Q: What particles were used in Rutherford's scattering experiment?** A: F...

 Class 9 Chapter 5 Cell  Q1: Who discovered the cell and when? A: Robert Hooke discovered the cell in 1665 by observing a thin slice of cork under a self-designed microscope. Q2: What does the word 'cell' mean? A: The word 'cell' is derived from a Latin word meaning a "little room" . Q3: Who was the first to discover free-living cells? A: Leeuwenhoek (1674) was the first to discover free-living cells in pond water using an improved microscope. Q4: Who coined the term 'protoplasm'? A: J.E. Purkinje (1839) coined the term 'protoplasm' for the fluid biological substance found within the cell. Q5: Who proposed the cell theory? A: Two biologists, M. Schleiden (1838) and T. Schwann (1839) , proposed the cell theory, which was later expanded by Virchow (1855) who stated that all cells arise from pre-existing cells. Q6: What is the plasma membrane also known as and why? A: The plasma membrane is known as a selectively permeable m...

 Class 9 Chapter 6 Tissue Q: What is a tissue? A: A tissue is a group of cells that are similar in structure and work together to achieve a particular function. Q: What type of tissue is responsible for the growth of plants in specific regions? A: The dividing tissue responsible for growth is known as meristematic tissue . Q: Which specific meristematic tissue increases the length of stems and roots? A: The apical meristem , located at the growing tips, increases the length of the stem and root. Q: What is the process of differentiation? A: Differentiation is the process by which cells formed by meristematic tissue take up a permanent shape, size, and function , resulting in permanent tissue. Q: Which simple permanent plant tissue is primarily responsible for storing food? A: The loosely arranged simple permanent tissue that generally stores food is called parenchyma . Q: What gives plants flexibility to bend in parts like tendrils without breaking? A: T...

 Class 9 Ch 12 Improvements in Food Resources                                          **General Agriculture & Food Sources** *   **What are the two major sources of food for humans?** Both plants and animals are the major sources of food for us. *   **What did the Green Revolution and White Revolution achieve?** The Green Revolution contributed to increased food-grain production, while the White Revolution led to the better availability and efficient use of milk. *   **Which crops are major sources of carbohydrates and proteins?** Cereals (wheat, rice, maize, millets) provide carbohydrates, and pulses (gram, pea, lentil) provide proteins. *   **What is the difference between *kharif* and *rabi* crops?** *Kharif* crops are grown in the rainy season (June to October), while *rabi* crops are grown in the winter season (November to April)...

 Class 9 Ch 11 Sound                                             **Q: What is sound and how is it produced?** A: Sound is a form of energy that produces a sensation of hearing, and it is produced by vibrating objects. **Q: What is a medium in the context of sound?** A: A medium is the matter or substance—whether solid, liquid, or gas—through which sound is transmitted from the point of generation to the listener. **Q: What type of waves are sound waves?** A: Sound waves are mechanical, longitudinal waves because they require a medium to travel and the particles of the medium oscillate back and forth parallel to the direction of wave propagation. **Q: What are compressions and rarefactions?** A: When a vibrating object moves forward, it pushes air to create a high-pressure region called a **compression (C)**, and when it moves backwards, it creates a low-pressure region...

 Class 9 ch 10 Work and Energy                                                                                                                                    **1. What are the two essential conditions for work to be done?** A force must act on an object, and the object must be displaced.  **2. How is work defined scientifically when a constant force is applied?** Work done is equal to the product of the magnitude of the force and the distance moved in the direction of the force ($W = F \times s$). **3. What is the SI unit of work and energy?** The unit of work and energy is the joule (J), which is equivalent to one newton-metre (1 N m). **4. When is...

 Class 9 Chapter 9 Gravitation Q: What force is responsible for the planets going around the Sun and the moon going around the earth? A: The gravitational force is responsible for these motions. Q: What keeps a body moving along a circular path? A: A centre-seeking force called the centripetal force keeps a body moving along a circular path. Q: What is the universal law of gravitation? A: It states that every object attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Q: What is the accepted value and SI unit of the universal gravitation constant ($G$)? A: The accepted value of $G$ is $6.673 \times 10^{-11} \text{ N m}^2 \text{ kg}^{-2}$ . Q: Who first discovered the value of the universal gravitation constant ($G$)? A: Henry Cavendish found the value of $G$ using a sensitive balance. Q: What does it mean for an object to be in "free fall...

 Class 9 Chapter 8 Force and Laws of Motion Q: What is required to accelerate the motion of an object or change its direction? A: An unbalanced force is required to accelerate an object or change its direction of motion. Q: What are balanced forces? A: Balanced forces are equal and opposite forces that do not change the state of rest or of motion of an object. Q: What is inertia? A: Inertia is the natural tendency of an object to resist a change in its state of rest or of uniform motion. Q: How is the inertia of an object measured quantitatively? A: The inertia of an object is measured by its mass . Q: What does Newton's first law of motion state? A: It states that an object remains in a state of rest or of uniform motion in a straight line unless compelled to change that state by an applied force. Q: What is momentum? A: Momentum is the product of an object's mass and its velocity ($p = mv$). Q: What is the SI unit of momentum? A: The SI unit of momentum is kilogram...

Class 9 chapter 7 Motion Q: What is the reference point used to describe the position of an object called? A: It is called the origin . Q: What is the shortest distance measured from the initial to the final position of an object known as? A: It is known as displacement . Q: Can the magnitude of displacement be zero? A: Yes , if the final position of an object coincides with its initial position, the displacement is zero, even if the distance covered is not zero. Q: What device is fitted in automobiles to measure the distance they have travelled? A: An odometer . Q: When is an object said to be in uniform motion? A: An object is in uniform motion when it covers equal distances in equal intervals of time . Q: What is the SI unit of speed? A: The SI unit of speed is metre per second (represented as m s–1 or m/s). Q: How is the average speed of an object calculated? A: Average speed is obtained by dividing the total distance travelled by the total time taken . Q: How...

Class 9 Moments: Literary Companion 📖 Moments | Class 9 Literary Companion Dashboard Stories Explore Your Characters Welcome to the interactive character guide for CBSE Class 9 English (Moments). Select a story from the sidebar to dive deep into character sketches, visualize traits, and test your memory. 📚 10 Stories ...

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