Maharashtra SSC Science and Technology (MSBSHSE) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Newton's law of gravitation

Every particle attracts every other with force F = G m1 m2 / r^2, where G is 6.67 × 10^-11 N m² kg^-2 and r is the separation between centres.

Escape velocity of Earth

The minimum speed needed for an object to leave Earth's gravitational field without further propulsion; it is about 11.2 km/s and equals √(2GM/R).

Newton's second law

The net external force on a body equals its mass times acceleration, F = ma; one newton is the force giving 1 kg an acceleration of 1 m/s².

Conservation of momentum

In a system with no net external force, total momentum before an interaction equals total momentum after; p = mv is a vector quantity.

Specific heat capacity

The heat needed to raise the temperature of 1 kg of a substance by 1 °C (or 1 K), given by Q = mcΔT; water's value is about 4200 J kg⁻¹ °C⁻¹.

Latent heat of fusion

The energy required to change 1 kg of a solid to liquid at its melting point without temperature change; for ice it is about 334 kJ/kg.

Snell's law

For light crossing a boundary, n1 sin i = n2 sin r, where n is refractive index and angles are measured from the normal; higher n means slower light.

Lens formula

For a thin lens, 1/f = 1/v − 1/u, with f focal length, v image distance and u object distance, using the sign convention; magnification m = v/u.

Ohm's law

At constant temperature, the current through a conductor is directly proportional to potential difference across it: V = IR, where R is resistance in ohms.

Fleming's left-hand rule

Predicts the direction of force on a current-carrying conductor in a magnetic field: thumb = force, forefinger = field, middle finger = current, all mutually perpendicular.

Balanced chemical equation

An equation with equal numbers of each type of atom on both sides, satisfying conservation of mass; coefficients are used and state symbols may be added.

Redox reaction

A reaction involving simultaneous oxidation and reduction; oxidation is loss of electrons or gain of oxygen, while reduction is gain of electrons or loss of oxygen.

pH scale

A logarithmic scale from 0 to 14 for hydrogen ion concentration; pH = −log[H+], values below 7 are acidic and above 7 are basic at 25 °C.

Neutralization reaction

The reaction of an acid with a base to form a salt and water, for example HCl + NaOH → NaCl + H2O; it is generally exothermic.

Modern periodic law

Properties of elements are periodic functions of their atomic number; elements are arranged in increasing atomic number in periods and groups.

Calcination

Heating an ore strongly in limited or no air to remove volatile impurities and convert carbonates or hydrated oxides into oxides, as in limestone to quicklime.

Catenation

The ability of carbon atoms to link with one another forming stable chains, branched chains and rings; it explains the very large number of carbon compounds.

Functional group

An atom or group of atoms attached to a carbon chain that determines characteristic chemical properties, such as −OH in alcohols or −COOH in carboxylic acids.

Addition polymerization

Formation of a polymer by repeated joining of unsaturated monomer molecules without loss of any small molecule, as in ethene forming polyethylene.

Homologous series

A family of organic compounds with the same functional group and general formula, in which successive members differ by one CH2 unit (14 u).

Osmosis

Movement of solvent molecules, usually water, through a selectively permeable membrane from a region of higher water potential to lower water potential.

Mitochondrion

A membrane-bound organelle that carries out aerobic respiration and releases energy as ATP; it is called the powerhouse of the eukaryotic cell.

Photosynthesis

The process by which green plants use chlorophyll and sunlight to convert carbon dioxide and water into glucose and oxygen: 6CO2 + 6H2O → C6H12O6 + 6O2.

Tissue culture

A biotechnology technique in which small pieces of plant or animal tissue are grown on a sterile nutrient medium to produce many identical individuals.

Mendel's law of segregation

During gamete formation the two alleles of a gene separate so that each gamete receives only one allele; they reunite randomly at fertilization.

Genotype and phenotype

Genotype is the genetic makeup of an organism, such as TT or Tt; phenotype is the observable trait produced by that genotype and the environment.

Natural selection

Darwin's mechanism of evolution: individuals with inherited variations better suited to the environment survive and reproduce more, increasing those traits in later generations.

Food chain

A linear sequence showing transfer of energy from producers to consumers, for example grass → grasshopper → frog → snake; arrows point in direction of energy flow.

Biomagnification

The increase in concentration of a non-biodegradable pollutant at successive trophic levels, because the pollutant is stored in body tissues and not excreted.

Solar photovoltaic cell

A device that converts sunlight directly into electrical energy using the photoelectric effect in semiconductor materials, commonly silicon; it produces direct current.

Earthquake epicentre

The point on Earth's surface directly above the focus, where seismic waves first reach the surface and damage is often greatest.

Biogas

A renewable fuel produced by anaerobic digestion of organic waste, mainly methane and carbon dioxide; it can be used for cooking and electricity generation.