9th class science question paper 2018 with answers

Students in class 9 need a strong foundation in science as it prepares them for advanced studies. This resource provides detailed questions and answers to help students understand key concepts of the 2018 class 9 science syllabus.

Physics Questions

Question What is the speed of light in a vacuum?
Answer The speed of light in a vacuum is approximately 3 × 10⁸ m/s.

Question Define acceleration.
Answer Acceleration is the rate of change of velocity of an object with time.

Question State Newton’s first law of motion.
Answer An object remains at rest or in uniform motion unless acted upon by an external force.

Question What is the SI unit of force?
Answer The SI unit of force is the newton (N).

Question What is uniform circular motion?
Answer It is motion in a circular path at a constant speed.

Question What is the formula for work done?
Answer Work done = Force × Displacement × cos(θ).

Question Define power.
Answer Power is the rate at which work is done or energy is transferred.

Question What is kinetic energy?
Answer Kinetic energy is the energy possessed by a body due to its motion.

Question State the law of conservation of energy.
Answer Energy cannot be created or destroyed; it can only change forms.

Question What is the formula for gravitational potential energy?
Answer Gravitational potential energy = mgh, where m = mass, g = acceleration due to gravity, and h = height.

Question What are longitudinal waves?
Answer Longitudinal waves are waves in which particles vibrate parallel to the direction of wave propagation.

Question Define frequency.
Answer Frequency is the number of oscillations per unit time.

Question What is the SI unit of pressure?
Answer The SI unit of pressure is the pascal (Pa).

Question What is inertia?
Answer Inertia is the property of a body to resist changes to its state of motion.

Question State the universal law of gravitation.
Answer Every mass attracts every other mass with a force proportional to the product of their masses and inversely proportional to the square of the distance between them.

Question Define moment of force.
Answer Moment of force is the turning effect produced by a force acting on an object.

Question What is the relationship between force and momentum?
Answer Force is the rate of change of momentum.

Question What is a simple pendulum?
Answer A simple pendulum consists of a mass attached to a string that swings back and forth under the influence of gravity.

Question What is the formula for pressure?
Answer Pressure = Force / Area.

Question What is mechanical advantage?
Answer Mechanical advantage is the ratio of output force to input force in a simple machine.

Chemistry Questions

Question Define matter.
Answer Matter is anything that has mass and occupies space.

Question What is an atom?
Answer An atom is the smallest unit of an element that retains its chemical properties.

Question What are isotopes?
Answer Isotopes are atoms of the same element with different numbers of neutrons.

Question Define a compound.
Answer A compound is a substance formed by the chemical combination of two or more elements in fixed proportions.

Question What is the pH scale?
Answer The pH scale measures the acidity or alkalinity of a solution.

Question What is a chemical reaction?
Answer A chemical reaction is a process in which substances interact to form new substances.

Question Define molar mass.
Answer Molar mass is the mass of one mole of a substance, expressed in grams per mole.

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

Question What are acids?
Answer Acids are substances that release hydrogen ions (H⁺) in aqueous solutions.

Question What are bases?
Answer Bases are substances that release hydroxide ions (OH⁻) in aqueous solutions.

Question Define periodic table.
Answer The periodic table is an arrangement of elements in order of increasing atomic number.

Question What are noble gases?
Answer Noble gases are elements in Group 18 of the periodic table that are chemically inert.

Question What is a covalent bond?
Answer A covalent bond is a chemical bond formed by the sharing of electrons between atoms.

Question What is an ionic bond?
Answer An ionic bond is a chemical bond formed by the transfer of electrons between atoms.

Question Define valency.
Answer Valency is the combining capacity of an element.

Question What is electrolysis?
Answer Electrolysis is the process of using an electric current to decompose a compound.

Question What is a catalyst?
Answer A catalyst is a substance that speeds up a chemical reaction without being consumed.

Question Define solubility.
Answer Solubility is the ability of a substance to dissolve in a solvent.

Question What is sublimation?
Answer Sublimation is the process of a solid changing directly into a gas without passing through the liquid state.

Question What is the law of conservation of mass?
Answer The law states that mass cannot be created or destroyed in a chemical reaction.

Biology Questions

Question What is a cell?
Answer A cell is the basic structural and functional unit of life.

Question What is photosynthesis?
Answer Photosynthesis is the process by which green plants synthesize food using sunlight, carbon dioxide, and water.

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

Question What is the function of the nucleus?
Answer The nucleus controls cellular activities and contains genetic material.

Question What is a tissue?
Answer A tissue is a group of similar cells that perform a specific function.

Question Define biodiversity.
Answer Biodiversity refers to the variety of life forms in an ecosystem.

Question What is respiration?
Answer Respiration is the biological process of breaking down glucose to produce energy.

Question What are xylem and phloem?
Answer Xylem transports water and minerals, while phloem transports food in plants.

Question What are the types of reproduction?
Answer Reproduction can be sexual or asexual.

Question Define ecosystem.
Answer An ecosystem is a community of living organisms interacting with their environment.

Question What is a food chain?
Answer A food chain is a series of organisms each dependent on the next for food.

Question Define genes.
Answer Genes are units of heredity that control the traits of an organism.

Question What is the function of mitochondria?
Answer Mitochondria are the powerhouses of the cell, producing energy in the form of ATP.

Question What is the role of chloroplasts?
Answer Chloroplasts are organelles in plants where photosynthesis occurs.

Question What is an adaptation?
Answer An adaptation is a feature that helps an organism survive in its environment.

Question Define excretion.
Answer Excretion is the process of removing waste products from the body.

Question What is a habitat?
Answer A habitat is the natural environment where an organism lives.

Question Define immunization.
Answer Immunization is the process of making an organism resistant to a disease through vaccination.

Question What is a pathogen?
Answer A pathogen is a microorganism that causes disease.

Studying past question papers like the 9th class science 2018 paper helps students prepare effectively for exams. It enhances understanding, boosts confidence, and identifies important topics.