Immediate and delayed effect of nuclear explosion.?

Question

Immediate and delayed effect of nuclear explosion.?

Answer 1

Blast, thermal radiation, and prompt ionizing radiation cause significant destruction within seconds or minutes of a nuclear detonation.

A fraction of a second after a nuclear explosion, the heat from the fireball causes a high-pressure wave to develop and move outward producing the blast effect. The front of the blast wave, the shock front, travels rapidly away from the fireball, a moving wall of highly compressed air.

The air immediately behind the shock front is accelerated to high velocities and creates a powerful wind. These winds, in turn, create dynamic pressure against the objects facing the blast. Shock waves cause a virtually instantaneous jump in pressure at the shock front. The combination of the pressure jump (called the overpressure) and the dynamic pressure causes blast damage. Both the overpressure and the dynamic pressure reach their maximum values upon the arrival of the shock wave. They then decay over a period ranging from a few tenths of a second to several seconds, depending on the blast's strength and the yield.

A primary form of energy from a nuclear explosion is thermal radiation. Initially, most of this energy goes into heating the bomb materials and the air in the vicinity of the blast. Temperatures of a nuclear explosion reach those in the interior of the sun, about 100,000,000° Celsius, and produce a brilliant fireball.

Two pulses of thermal radiation emerge from the fireball. The first pulse, which lasts about a tenth of a second, consists of radiation in the ultraviolet region. The second pulse which may last for several seconds, carries about 99 percent of the total thermal radiation energy. It is this radiation that is the main cause of skin burns and eye injuries suffered by exposed individuals and causes combustible materials to break into flames.

Thermal radiation damage depends very strongly on weather conditions. Clouds or smoke in the air can considerably reduce effective damage ranges versus clear air conditions.

The release of radiation is a phenomenon unique to nuclear explosions. There are several kinds of radiation emitted; these types include gamma, neutron, and ionizing radiation, and are emitted not only at the time of detonation (initial radiation) but also for long periods of time afterward (residual radiation).

The delayed effects, such as radioactive fallout and other environmental effects, inflict damage over an extended period ranging from hours to years.  The list of possible negative effects is quite lengthy.  To read about these, go to:

http://www.atomicarchive.com/Effects/eff...