"The Cosmic Engine" Physics Course
Cosmic Engine - Research Task
1. Describe how energy can be released from the nuclei of atoms (6)
Most nuclei are stable. Consisting of protons and neutrons, they are unaffected by chemical reactions and have remained the same since they were formed. However, some nuclei are unstable and spontaneously release energy in the form of a Helium nucleus (α Alpha),an electron (β Beta) and γ Gamma rays. These nuclei are known as radioactive and it’s not possible to predict when a particular radioactive nucleus will emit this energy but a large number of materials are said to have a ‘half life’. The half life is the time it takes for half the nuclei to emit their radiation.
1. Describe and compare the nature of emissions from the nuclei of atoms as radiation of alpha α and beta β particles and gamma γ rays in terms of: (6) Ionising power Penetrating power Effect of magnetic field Effect of electric Field Alpha Particles: Alpha particles are composed of two protons and two neutrons and have the same nucleus as Helium. It is a very stable particle. Large nuclei such as Americium-241 emit alpha particles. As it emits alpha particles its mass and atomic number decrease, so it changes into a different element. Alpha particles are good ionizers because of their double positive charge, large mass and because they are relatively slow compared to beta particles. They can also cause multiple ionizations within a very small distance. Because alpha particles are highly ionizing, they are unable to penetrate very far through matter and are brought to rest by a few centimeters of air or less than a tenth of a millimeter of living tissue. After traveling through air for a few centimeters, it will capture electrons and become a Helium atom. Because alpha particles possess the charge of two protons, when they move through a magnetic or electric field a force is exerted on
1. Describe how energy can be released from the nuclei of atoms (6)
Most nuclei are stable. Consisting of protons and neutrons, they are unaffected by chemical reactions and have remained the same since they were formed. However, some nuclei are unstable and spontaneously release energy in the form of a Helium nucleus (α Alpha),an electron (β Beta) and γ Gamma rays. These nuclei are known as radioactive and it’s not possible to predict when a particular radioactive nucleus will emit this energy but a large number of materials are said to have a ‘half life’. The half life is the time it takes for half the nuclei to emit their radiation.
1. Describe and compare the nature of emissions from the nuclei of atoms as radiation of alpha α and beta β particles and gamma γ rays in terms of: (6) Ionising power Penetrating power Effect of magnetic field Effect of electric Field Alpha Particles: Alpha particles are composed of two protons and two neutrons and have the same nucleus as Helium. It is a very stable particle. Large nuclei such as Americium-241 emit alpha particles. As it emits alpha particles its mass and atomic number decrease, so it changes into a different element. Alpha particles are good ionizers because of their double positive charge, large mass and because they are relatively slow compared to beta particles. They can also cause multiple ionizations within a very small distance. Because alpha particles are highly ionizing, they are unable to penetrate very far through matter and are brought to rest by a few centimeters of air or less than a tenth of a millimeter of living tissue. After traveling through air for a few centimeters, it will capture electrons and become a Helium atom. Because alpha particles possess the charge of two protons, when they move through a magnetic or electric field a force is exerted on