9th science half yearly question paper 2019

The 9th Science half-yearly examination helps students assess their understanding of key scientific concepts. This set of questions and answers covers various types of questions, including objective, short, and long answers, to aid preparation. Students can use this guide to revise and gain confidence for their exams effectively.

Physics

Question: What is the first law of motion?

Answer: An object remains in a state of rest or uniform motion in a straight line unless acted upon by an external force.

Question: Define acceleration.

Answer: Acceleration is the rate of change of velocity of an object with respect to time.

Question: State the unit of force.

Answer: The unit of force is Newton (N).

Question: What is the formula for calculating work?

Answer: Work = Force × Distance × cos(θ).

Question: Define inertia.

Answer: Inertia is the tendency of an object to resist changes in its state of motion or rest.

Question: What is the value of acceleration due to gravity on Earth?

Answer: The value of acceleration due to gravity on Earth is approximately 9.8 m/s².

Question: What is the SI unit of energy?

Answer: The SI unit of energy is the Joule (J).

Question: Define potential energy.

Answer: Potential energy is the energy possessed by an object due to its position or configuration.

Question: State the law of conservation of energy.

Answer: Energy can neither be created nor destroyed; it can only be transformed from one form to another.

Question: What is the formula for kinetic energy?

Answer: Kinetic Energy = ½ × Mass × Velocity².

Question: Define displacement.

Answer: Displacement is the shortest distance between the initial and final position of an object.

Question: What is a scalar quantity?

Answer: A scalar quantity is a physical quantity that has only magnitude and no direction.

Question: What is the unit of power?

Answer: The unit of power is the Watt (W).

Question: Define momentum.

Answer: Momentum is the product of an object’s mass and its velocity.

Question: State Newton’s second law of motion.

Answer: The force acting on an object is equal to the rate of change of its momentum.

Question: What is the unit of pressure?

Answer: The unit of pressure is Pascal (Pa).

Question: Define density.

Answer: Density is the mass of an object per unit volume.

Question: What is Archimedes’ principle?

Answer: Archimedes’ principle states that a body immersed in a fluid experiences an upward force equal to the weight of the fluid displaced.

Question: Define refraction.

Answer: Refraction is the bending of light when it passes from one medium to another with a different density.

Chemistry

Question: What is the chemical formula for water?

Answer: The chemical formula for water is H₂O.

Question: Define valency.

Answer: Valency is the combining capacity of an element to form a compound.

Question: What is an acid?

Answer: An acid is a substance that releases hydrogen ions (H⁺) in an aqueous solution.

Question: What is the pH value of a neutral solution?

Answer: The pH value of a neutral solution is 7.

Question: Define a mixture.

Answer: A mixture is a combination of two or more substances that are not chemically bonded.

Question: What is the atomic number of oxygen?

Answer: The atomic number of oxygen is 8.

Question: What is the difference between an atom and a molecule?

Answer: An atom is the smallest unit of an element, while a molecule is a group of two or more atoms bonded together.

Question: What is the chemical formula for common salt?

Answer: The chemical formula for common salt is NaCl.

Question: Define an isotope.

Answer: Isotopes are atoms of the same element with the same number of protons but a different number of neutrons.

Question: What is the law of conservation of mass?

Answer: Mass can neither be created nor destroyed in a chemical reaction.

Question: What is an alloy?

Answer: An alloy is a mixture of two or more metals or a metal and a non-metal.

Question: Define a catalyst.

Answer: A catalyst is a substance that increases the rate of a chemical reaction without undergoing permanent change.

Question: What is the molecular formula of carbon dioxide?

Answer: The molecular formula of carbon dioxide is CO₂.

Question: What is a covalent bond?

Answer: A covalent bond is a chemical bond formed by the sharing of electron pairs between atoms.

Question: Define electrolysis.

Answer: Electrolysis is the process of using an electric current to decompose a compound into its elements.

Question: What is the symbol of gold?

Answer: The symbol of gold is Au.

Question: What are noble gases?

Answer: Noble gases are elements in Group 18 of the periodic table that are inert and stable.

Question: Define a base.

Answer: A base is a substance that releases hydroxide ions (OH⁻) in an aqueous solution.

Question: What is the periodic table?

Answer: The periodic table is a tabular arrangement of elements based on their atomic numbers, electron configurations, and chemical properties.

Biology

Question: What is the basic unit of life?

Answer: The basic unit of life is the cell.

Question: Define photosynthesis.

Answer: Photosynthesis is the process by which green plants synthesize food using sunlight, carbon dioxide, and water.

Question: What is the function of the nucleus in a cell?

Answer: The nucleus controls cellular activities and contains genetic material.

Question: What are the components of the human digestive system?

Answer: The human digestive system includes the mouth, esophagus, stomach, intestines, liver, and pancreas.

Question: Define an ecosystem.

Answer: An ecosystem is a community of living organisms interacting with their physical environment.

Question: What is the role of red blood cells?

Answer: Red blood cells transport oxygen throughout the body.

Question: Define a habitat.

Answer: A habitat is the natural environment where an organism lives.

Question: What is the function of chlorophyll?

Answer: Chlorophyll absorbs light energy for photosynthesis.

Question: Define reproduction.

Answer: Reproduction is the biological process by which organisms produce offspring.

Question: What are genes?

Answer: Genes are units of heredity that carry information from parents to offspring.

Question: What is the function of the heart?

Answer: The heart pumps blood throughout the body.

Question: Define excretion.

Answer: Excretion is the process of removing waste products from the body.

Question: What is biodiversity?

Answer: Biodiversity is the variety of life forms in a particular ecosystem or on Earth.

Question: What is the function of the brain?

Answer: The brain controls and coordinates body functions.

Question: What is osmosis?

Answer: Osmosis is the movement of water molecules from a region of lower solute concentration to a region of higher solute concentration through a semi-permeable membrane.

Question: Define a food chain.

Answer: A food chain shows the transfer of energy and nutrients from one organism to another.

Question: What is the role of the kidneys?

Answer: The kidneys filter blood and produce urine.

Question: Define respiration.

Answer: Respiration is the process by which organisms break down glucose to release energy.

Question: What is the role of the lungs?

Answer: The lungs facilitate the exchange of oxygen and carbon dioxide during breathing.

The 9th Science half-yearly examination 2019 focuses on critical concepts from Physics, Chemistry, and Biology. Understanding these fundamental questions will prepare students for their exams and enhance their scientific knowledge. Practice thoroughly to strengthen your concepts and achieve excellent results.