Radioactivity and Its Types
This lesson covers the definition of radioactivity and the characteristics of radioactive elements. It explains the three types of radiation: alpha particles, beta particles, and gamma rays, along with their properties. The lesson also includes the concept of half-life and decay constants.
- 12:30 “remain. So that means it will take 30 years to lose 7 over 8 of these original atoms. Because if you subtract, we said n is the original atom. So if you subtract n over 8 from n, it will give you 7 n over 8. So that mean...”
- 01:39 “elements that disintegrate spontaneously and emit radiation from their nucleus. Example of radioactive elements are uranium, radium, polonium, ionium, sodium and so on and so forth. We have three types of radiations that...”
- 04:05 “electrical in neutral. That is they have no charge. They have negligible mass. They have high penetrating power in A and solid and several meters in lead. They are not deflected by magnetic field. This is because they ha...”
Particulate Nature of Matter
The lesson covers the distinction between physical and chemical changes, including examples. It explains the difference between atoms and molecules, describes the arrangement of particles in an atom, and defines atomic number, mass number, and isotopes. The calculation of relative atomic masses of a
- 21:48 “Let's remember that proton is positively charged. Electron is negatively charged. So, if they are the same. It means I have plus two minus two. Remember that neutron is neutral. So, an atom is electrically neutral. No ch...”
- 15:41 “And then it was discovered that Dalton atomic theory needs to be modified. Dalton said atoms are composed of small, indivisible particles of an element, but it was discovered that an atom has particles, an atom has a nuc...”
- 18:15 “and electrons. Now, atoms ask the nucleus, which I said has two particles. We have the protons and the neutron that these two forms the nucleus. And outside the nucleus, there are some negative particles called the elect...”
Work, Energy and Power
This lesson covers the definitions of work, energy, and power. It includes calculations for work done, gravitational potential energy, and power in watts. The lesson also distinguishes between kinetic and potential energy and explains energy transformation and the law of conservation of energy.
- 11:20 “This energy emanates from the changes in the nucleus of an atom or from nuclear reactions. Take, for example, bombing. We'll talk about bomb fusion or fusion. It is common knowledge that, when there is war, there's alway...”
- 10:30 “Take, for example, hot water and cold water. The temperature difference between them, most of the way, you pour hot water or cold water in hot water, the hot water will supply heat to the cold water. So that at the end o...”
- 00:00 “Good day everyone. My name is Tabelo A.E. the physicist here for today. The topic we are examining today is work, energy and power. The lesson objectives are at the end of the lesson the students will be able to one defi...”
Sources of Energy
The lesson covers different sources of energy, including renewable and non-renewable types. It explains how energy is used in society and discusses the environmental impacts of various energy sources. Specific examples include petroleum, natural gas, solar energy, and wind energy.
- 03:55 “and also in gaseous form. We are told that in liquids, the liquid petrol naturally in reservoir is called the crude oil, which you already know, crude oil, and gas petrol oil is the first as natural gas. How we are told...”
- 04:41 “we see that what a lot of nuclear energy is being released. Even in our society today, even in our environment, nuclear energy is what is being released in large amounts. It's being released every day, every second, ever...”
- 00:02 “Good day, class. My name is Eme Nnamdi John. I'll be taking you on physics, through the topic, energy and society. Now, our first objective today, at the end of the study, Lena should be able to know one, the source of e...”
Changes of Matter and Atomic Structure
The lesson covers the differences between physical and chemical changes in matter. It explains the concepts of atoms and molecules, their arrangements, and introduces atomic number, mass number, and isotopes. The lesson also includes calculations of relative atomic masses.
- 03:14 “The nest is Dalton's atomic theory, and according to Dalton in 1808, it proposed some theories, which form the basis for atoms. The first is all elements are made up of small individual particles, called atom. The nest i...”
- 04:05 “The proton is positively charged, and the neutron is neutral, why the electron is negatively charged. The proton and the neutron are in the nucleus. High electron revolve around the orbits. Atoms are electrical in neutra...”
- 07:25 “If you evaluate very well, which I am now having completed with me, you do that. You have 26.5, 26.25 here, and then you have 9.35 here. If you send them together, you discover the relative atomic mass of chlorine will g...”
Gravitational Force and Fields
The lesson covers the concept of gravitational fields and the laws of gravitational force as proposed by Isaac Newton. It explains the relationship between masses and the distance between them in determining gravitational force.
- 26:53 “watching, I am Emina Di Jong, see you next time.”
- 24:19 “here, now let's get this, 6.67 times 42 times 10 raise to the power, let's have this 42 times 6.67 or give us as we have this 28 0.14 times 10 raise to the power minus 9, over”
- 26:05 “now I can have it to the power 1, 2 to be F is equal to 7.0.035 times, if that is by 2 this will reduce by 2 10 raise to the power minus 7 new team and that is the answer for the force, so our like us to take the number...”