Bihar BSEB Matric Science flashcards

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

Balanced chemical equation

An equation in which the number of atoms of each element is equal on both sides, satisfying the law of conservation of mass.

Rusting of iron

Iron reacts with oxygen and moisture to form hydrated iron(III) oxide, a reddish-brown flaky coating; prevented by painting, greasing or galvanising.

pH scale

A scale from 0 to 14 measuring hydrogen ion concentration: below 7 acidic, 7 neutral, above 7 basic. One unit means a tenfold change.

Neutralisation reaction

The reaction of an acid with a base that produces salt and water only, for example HCl + NaOH gives NaCl + H2O and releases heat.

Reactivity series

A list of metals in decreasing order of chemical reactivity from potassium to gold; metals above hydrogen displace it from dilute acids.

Galvanisation

Coating iron or steel with a layer of zinc to prevent rusting, because zinc corrodes first and protects the iron beneath.

Catenation

The ability of carbon atoms to link with one another forming long chains, branches and rings, explaining the very large number of carbon compounds.

Esterification

Reaction of a carboxylic acid with an alcohol in the presence of a little concentrated sulphuric acid, giving an ester with a fruity smell.

Modern periodic law

The properties of elements are periodic functions of their atomic number; elements are arranged in seven periods and eighteen groups.

Atomic radius trend

Atomic radius decreases across a period as nuclear charge increases with the same number of shells, and increases down a group as shells are added.

Mirror formula

The relation 1/v + 1/u = 1/f connecting image distance, object distance and focal length of a spherical mirror, with signs as per convention.

Refractive index

The ratio of the speed of light in vacuum to that in a medium, or sine of angle of incidence to sine of angle of refraction.

Myopia

Short-sightedness in which a distant object is focused in front of the retina, so the person cannot see far objects clearly; corrected by a concave lens.

Dispersion of light

The splitting of white light into seven component colours when it passes through a prism, with violet deviated most and red least.

Ohm's law

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

Electric power

The rate at which electrical energy is consumed, given by P = VI = I squared R = V squared divided by R; measured in watt.

Fleming's left-hand rule

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

Electromagnetic induction

The production of an induced current in a coil when the magnetic field linked with it changes, discovered by Faraday and used in generators.

Biogas

A fuel gas, mainly methane, produced when cow dung or plant waste is decomposed by bacteria without air; used for cooking and lighting.

Solar cell

A silicon device that converts solar energy directly into electricity without any moving parts, used in satellites and remote lighting.

Stomata

Small pores on the leaf surface, bordered by guard cells, that regulate the exchange of gases and the loss of water vapour.

Double circulation

Blood passes twice through the heart in one complete cycle, once through the lungs and once through the rest of the body.

Reflex arc

The pathway of a nerve impulse in a reflex action: receptor, sensory nerve, spinal cord, motor nerve and finally the muscle.

Auxin

A plant hormone made at shoot tips that promotes cell elongation and causes the shoot to bend towards light, that is phototropism.

Binary fission

Asexual reproduction in which a single-celled organism such as Amoeba divides into two similar daughter cells after duplicating its nucleus.

Placenta

A disc-like tissue joining the embryo to the uterine wall that allows exchange of glucose, oxygen and waste materials with the mother.

Dominant trait

A trait that appears in the offspring even when only one copy of its gene is present, as tallness T dominates over dwarfness t.

Homologous organs

Organs with the same basic structure but different functions, such as the human forelimb and the bird wing; they indicate common ancestry.

Ten per cent law

Only about ten per cent of the energy at one trophic level is transferred to the next level; the rest is lost mainly as heat.

Biodegradable waste

Waste that microorganisms can break down, such as vegetable peels and paper, unlike plastic which persists in the environment for decades.

Rainwater harvesting

Collecting and storing rainwater running off rooftops, roads or check dams so that it can be reused or used to recharge groundwater.

Chipko movement

A movement in the Himalayan region where local people hugged trees to stop them being felled, showing community-led forest conservation.