Odisha BSE Madhyama Science flashcards

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

Ohm's law

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

Series resistance formula

For resistors joined end to end, the equivalent resistance is the sum of individual resistances: R = R1 + R2 + R3, and the same current flows through each.

Parallel resistance formula

For resistors connected across the same two points, the reciprocal of equivalent resistance equals the sum of reciprocals: 1/R = 1/R1 + 1/R2.

Electric power

The rate at which electrical energy is consumed, given by P = VI = I²R = V²/R and measured in watts; one kilowatt-hour is one commercial unit.

Mirror formula

The relation 1/v + 1/u = 1/f connecting image distance, object distance and focal length of a spherical mirror, with distances measured using the sign convention.

Lens formula and power

The relation 1/v - 1/u = 1/f for a lens; power equals 1/f in metres, measured in dioptres, positive for a converging convex lens.

Refractive index

The ratio of the speed of light in vacuum to its speed in a medium, n = c/v; a higher value means the medium is optically denser and bends light more.

Total internal reflection

When light travels from a denser to a rarer medium at an angle greater than the critical angle, it is completely reflected back into the denser medium.

Fleming's left-hand rule

Rule giving the direction of force on a current-carrying conductor in a magnetic field: thumb shows force, forefinger field, middle finger current.

Law of conservation of mass

In a chemical reaction, matter is neither created nor destroyed, so the total mass of reactants equals the total mass of products formed.

Neutralisation reaction

A reaction in which an acid reacts with a base to form a salt and water, releasing heat; for example hydrochloric acid with sodium hydroxide gives sodium chloride.

Oxidation and reduction

Oxidation is gain of oxygen or loss of electrons; reduction is loss of oxygen or gain of electrons; both occur together in a redox reaction.

Mole concept

One mole of a substance contains 6.022 × 10²³ particles and has a mass in grams equal to its atomic or molecular mass.

pH scale

A scale from 0 to 14 measuring hydrogen ion concentration; values below 7 are acidic, 7 is neutral and above 7 is basic at room temperature.

Photosynthesis equation

Green plants use chlorophyll and sunlight to combine carbon dioxide and water into glucose, releasing oxygen: 6CO2 + 6H2O → C6H12O6 + 6O2.

Xylem and phloem

Xylem conducts water and dissolved minerals upward from roots; phloem transports prepared food from leaves to other parts of the plant.

Stomata function

Microscopic pores on leaf surfaces, bordered by guard cells, that permit exchange of carbon dioxide, oxygen and water vapour with the atmosphere.

Nephron

The microscopic functional unit of the kidney that filters blood, reabsorbs useful substances such as glucose and water, and forms urine.

Mendel's law of segregation

During gamete formation the two alleles of a gene separate so each gamete receives only one; the dominant allele masks the recessive in the offspring.

Newton's second law

The net force on a body equals the product of its mass and acceleration, F = ma; force is measured in newtons and acceleration in m/s².

Kinetic and potential energy

Kinetic energy of a moving body is ½mv²; gravitational potential energy at height h is mgh; in free fall one converts into the other.

Law of gravitation

Every two bodies attract each other with force F = Gm1m2/r², where G is 6.67 × 10⁻¹¹ N·m²/kg² and r is the distance between their centres.

Law of conservation of momentum

In the absence of external forces, the total momentum of an isolated system remains constant before and after a collision or interaction.

Velocity-time graph

A graph plotting velocity against time; its slope gives acceleration and the area enclosed under it gives the distance travelled by the body.

Newton's third law

For every action force there is an equal and opposite reaction force; the two act on different bodies and therefore never cancel each other.

Latent heat

The hidden heat absorbed or released during a change of state at constant temperature; latent heat of fusion of ice is about 80 calories per gram.

Atomic number and mass number

Atomic number is the count of protons in a nucleus; mass number is the count of protons plus neutrons; isotopes differ in mass number only.

Ionic and covalent bonds

Ionic bonds form by complete transfer of electrons from metal to non-metal; covalent bonds form by sharing of electron pairs between non-metal atoms.

Mitosis and meiosis

Mitosis gives two identical diploid cells for growth and repair; meiosis gives four haploid gametes and creates genetic variation through crossing over.

Five-kingdom classification

The grouping of living organisms into Monera, Protista, Fungi, Plantae and Animalia based on cell type, body organisation and mode of nutrition.

Food chain energy flow

Energy passes from producers to herbivores and then to carnivores; only about ten per cent of energy at one trophic level reaches the next.

Dispersion of light

The splitting of white light into its seven constituent colours when it passes through a prism, because each colour has a different refractive index.