Radioactivity & Nuclear Energy

Time taken for a sample of radioactive nuclei to decay to half of its initial number is known as

• Half Time

• Half Life

• Radioactivity

• Uranium -235

If the ratio of Pb : U is 3:1 , it is means that

• there is 25 % of Pb and 75 % of U

• there is 25 % of decayed nuclei and 75 % of undecayed nuclei

• undergoes 2 half life

• undergoes 3 half life

A sample of radioactive material stored in the laboratory has an initial activity of 480 s(-1). its half life is 6 minutes, how much is it activity after 30 minutes?

• 5 s^(-1)

• 15 s^(-1)

• 150 s^-1

....................................... is aprocess of unstable nucleus becomes more stable by emitting radioactive radiation.

• half life

• Beta particle

• Radioactive decay

• Nuclear Energy

................... atomic energy released during nuclear reaction such as radioactive decay, nuclear fission and nuclear fusion

• Fission Energy

• Fusion Energy

• Nuclear Energy

• Radioactive Energy

Nuclear Fission is ..............

• atomic energy, released during nuclear reactions such as radioactive decay, nuclear fission and nuclear fusion.

• a nuclear reaction when a heavy nucleus splits into two or more lighter nuclei while releasing a large amount of energy

• a nuclear reaction in which small and light nuclei fuse to form a heavier nucleus while releasing a large amount of energy.

Boron or cadmium place in nuclear reactor , function as

• Moderator

• cooling agent

• control rod

The purpose of control rod in nuclear reactor is ............

• Slow down the fast moving neutrons

• Absorbing excess neutrons in order to control reaction rate

• used as fuels for producing nuclear energy

which of the material below used as moderator in nuclear reactor

• Graphite

• Boron

• Cadmium

• Uranium

Which of the statement below, explain about the function of moderator.

• prevent radioations from leaking

• Slow down the fast moving neurons

• Control the reactor temperature