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Questions and Answers
What is a key characteristic of alternating current (AC)?
Which of the following sources is associated with direct current (DC)?
What determines the maximum number of electrons a shell can hold in an atom?
Which of the following is a type of alternating current?
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What is the number of electrons that the L shell can hold?
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Which statement is true regarding direct current (DC)?
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What is a characteristic of pulsating direct current (DC)?
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Which of the following types of current can sometimes have a single polarity?
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What is the outermost shell of an atom called?
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What happens to valence electrons when energy is applied?
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Which of the following best describes free electrons?
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Why are valence electrons essential in the structure of an atom?
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What is the relationship between valence shell and free electrons?
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Study Notes
AC vs DC
- AC (Alternating Current) changes direction periodically, while DC (Direct Current) flows in one direction.
- AC has both positive and negative polarity, while DC can have single polarity.
- AC sources include main supply and generators, while DC sources include batteries, cells, and solar panels.
- AC types include sinusoidal, triangular, and square waves, while DC types include regulated (fixed) and pulsating.
Structure of an Atom
- Atoms consist of protons, neutrons, and electrons.
- Protons are positively charged, electrons are negatively charged, and neutrons have no charge.
- Electrons orbit the nucleus in shells, with each shell having a specific maximum number of electrons.
Shells/Orbits
- The maximum number of electrons a shell can hold is 2n², where n is the shell number.
- The first (K) shell can hold 2 electrons (2 x 1²), the second (L) shell can hold 8 (2 x 2²), and the third (M) shell can hold 18 (2 x 3²).
Valence Shell and Valence Electrons
- The outermost shell of an atom is called the valence shell, and the electrons in that shell are called valence electrons.
- Valence electrons are loosely attached to the nucleus, making them more likely to participate in chemical reactions.
Free Electrons
- Valence electrons can be pulled away from the parent atom and become "free electrons" when exposed to external energy, like heat or light.
- Free electrons are responsible for electrical conductivity in materials because they can readily move between atoms.
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Description
Explore the fundamental concepts of alternating and direct current, along with the structure of an atom. This quiz covers AC vs DC characteristics, atomic particles, shell configurations, and valence electrons. Test your knowledge in these essential physics topics!
