B
Background Radiation
Background radiation is the radiation which occurs naturally in the rocks, air and water around us.
Battery
A battery is a number (or battery) of cells, connected in series with the positive terminal of one cell connected to the negative of the next. Batteries provide a d.c.(direct current) source of electrical energy.
Beam
The particle stream produced by an accelerator usually clustered in bunches.
b (beta) radiation
b (beta) radiation consists of fast moving electrons. These electrons are produced as a result of transitions that take place in unstable nuclei. b radiation can be stopped by a few millimetres of aluminium. It is an ionising radiation, not as strongly ionising as a (alpha) radiation.
Big-bang Theory
The 'big-bang theory' of cosmology tries to explain the origin of the universe as an explosive event, where space, time and matter came into being.
Black Hole
A collapsed star from which no light can escape, due to the intense gravitational field.
Block Diagram
In electronics, a block diagram provides a simple way of analysing how a system works. Block diagrams don't show details of how components work, but simply show how information or signals should travel through the system. They are usually drawn using rectangles and arrows.