Maharashtra SSC Science and Technology (MSBSHSE) key terms

The mutual pull between any two masses. It grows with the size of the masses and weakens with the square of the distance between them, keeping planets in orbit and objects on the ground.

The minimum speed an object needs to move away from a planet or moon forever without any further push. For Earth it is about 11.2 kilometres per second.

The rate at which a body's momentum changes is directly proportional to the net force applied, and the change happens in the direction of that force. For constant mass this gives F = ma.

A vector quantity equal to an object's mass multiplied by its velocity. It measures how difficult the object is to stop; in a closed system total momentum stays constant.

The amount of heat energy required to raise the temperature of one kilogram of a substance by one degree Celsius, or one kelvin. Water has an unusually high value.

The unusual behaviour in which water contracts as it is heated from 0 °C to 4 °C and expands above 4 °C, so its density is greatest at 4 °C.

The ratio of the speed of light in a vacuum to its speed in a given medium. It shows how strongly the medium bends light entering it; larger values mean more bending.

The complete bouncing back of light into a denser medium when it strikes the boundary with a rarer medium at an angle larger than the critical angle.

The reciprocal of the focal length of a lens measured in metres, expressed in dioptres. A positive value means a converging lens, a negative value a diverging lens.

At constant temperature, the current flowing through a metallic conductor is directly proportional to the potential difference across its ends, so V = IR.

The production of a potential difference, and hence a current, in a conductor when the magnetic field around it changes. Generators and transformers work on this principle.

A symbolic way of writing a chemical reaction in which the number of atoms of each element is equal on both sides, showing that mass is conserved.

A chemical change in which a substance loses electrons, gains oxygen, or loses hydrogen. Its oxidation number increases during the change.

A scale from 0 to 14 that expresses how acidic or basic a solution is. Values below 7 are acidic, 7 is neutral, and values above 7 are basic.

The reaction between an acid and a base that produces a salt and water. The acidic and basic properties of both reactants are lost.

An ionic compound produced when the hydrogen ion of an acid is replaced by a metal ion or an ammonium ion, commonly during neutralisation.

The set of industrial processes used to obtain a pure metal from its ore, including concentration of the ore, roasting or calcination, reduction, and refining.

A solid mixture of a metal with one or more other elements, made to improve properties such as hardness, strength, or resistance to corrosion.

The ability of an element, especially carbon, to join repeatedly with atoms of itself to form straight chains, branched chains, or rings.

A specific atom or group of atoms attached to a carbon chain that gives the compound its characteristic chemical properties, for example the –OH group in alcohols.

A family of carbon compounds with the same functional group and similar chemical properties, in which consecutive members differ by one –CH₂– unit.

A chemical reaction in which many small molecules called monomers join together repeatedly to form a very large molecule known as a polymer.

Membrane-bound organelles in which aerobic respiration takes place, releasing energy from food as ATP. They are present in large numbers in active cells.

The thin, flexible, selectively permeable boundary around a cell, made mainly of lipids and proteins, which controls what enters and leaves.

A type of cell division that produces two daughter cells with the same number of chromosomes as the parent cell. It is used for growth and repair.

The process by which green plants use sunlight, carbon dioxide, and water to make glucose and release oxygen, with chlorophyll absorbing the light energy.

The process in living cells that breaks down food molecules to release energy. Aerobic respiration uses oxygen and gives carbon dioxide and water.

The deliberate alteration of an organism's genes by modern laboratory methods, such as inserting a useful gene into a bacterium or crop plant.

A section of DNA that carries the instructions for making a protein or controlling a characteristic, and is passed from parents to offspring.

The process by which individuals with traits better suited to their surroundings survive and reproduce more, so those traits become more common over generations.

The variety of life in a place, covering the range of different species, the genetic differences within each species, and the ecosystems they form.

Development that satisfies present needs without reducing the ability of future generations to meet their own needs, balancing economic growth with environmental care.

A sequence of organisms showing how energy passes from a producer, such as a plant, to herbivores and then to carnivores that eat them.

Energy obtained from sources that are naturally replenished in a short time, such as sunlight, wind, flowing water, biomass, and geothermal heat.

The organised cycle of prevention, preparedness, response, and recovery that aims to reduce the harm a disaster causes to people and property.

Measures taken before a hazard strikes to reduce the damage it can cause, such as building embankments, planting trees, or enforcing earthquake-safe construction.

A chart in which elements are arranged by increasing atomic number, with elements having similar properties placed in the same vertical group.

The existence of two or more compounds that share the same molecular formula but have different arrangements of atoms, and therefore different properties.