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Questions and Answers
What is an atom?
The smallest unit of ordinary matter that forms a chemical element.
What is ionization?
The process by which an atom or molecule acquires a negative or positive charge.
What are the types of charge?
Charge can be created or destroyed.
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What does voltage represent in electricity?
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What is the unit of electrical force?
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What is current?
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Which type of materials generally allows better current flow?
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Study Notes
Structure of an Atom
- Atoms are the smallest unit of matter
- They have a nucleus with protons and neutrons
- Electrons orbit the nucleus
- Protons have a positive charge, electrons have a negative charge, and neutrons have no charge
- Atoms are electrically neutral if there are an equal number of protons and electrons
- Atoms with more or fewer electrons are called ions
Ionization
- It is the process by which an atom gains or loses an electron
- This results in a negatively or positively charged ion
Charge
- The basic property of electromagnetic force
- Used by living cells to communicate
- Measured in coulombs (C) or microcoulombs (C)
- Occurs due to external forces such as friction, heat, or chemical/electrical sources
Properties of electrical charge
- There are two types of charge: positive and negative
- Like charges repel each other
- Opposite charges attract
- Charge can be transferred between objects
Polarity and Electric Fields
- In a circuit, one electrode is positive and the other is negative
- The negative electrode is called the cathode
- The positive electrode is called the anode
- Electric fields are also called voltage
Voltage
- Represents potential energy in an electric field
- The greater the force, the greater the potential energy
- Measured in volts (V) or millivolts (mV)
- Analogous to the force between two magnets, or charged bodies as they approach each other
- Can also be called electromotive force (EMF) or electrical potential energy
Current
- Movement of ions or electrons in a conductor in response to a voltage force
- The flow of current is directly proportional to the magnitude of the voltage
- Measured in amperes (A), or milliamperes (mA)
- In the human body, the charged particles are ions such as sodium (Na+), potassium (K+), and chloride (Cl–)
Factors affecting Current Flow through Tissues
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- Conduction Characteristics: The more electrons a material has, the less resistance and the better current flow. Example: blood and nerves have more free electrons than skin or bone, so current prefers to travel along these tissues
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- Cross-Sectional Area: Greater cross-sectional areas of tissue will allow larger current flow
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- Length of the Conducting Path: Longer paths have higher resistance
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- Temperature: Higher temperature increases the number of free electrons, thus improving conduction
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- Frequency: Higher frequency currents are more likely to pass through the tissue
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- Density: Tissues with high water content carry current better than those with low water content
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- Phase of Tissue: Current flow is affected by the amount of injury to tissue
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- Electrode Position: Positioning of the electrodes influences the path of current flow
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Description
This quiz explores the fundamental concepts of atomic structure, ionization, and the properties of electrical charge. Test your understanding of how protons, neutrons, and electrons interact and the role of charge in communication among living cells. Ideal for students seeking to deepen their knowledge of basic chemistry and physics.
