Physical Science Chapter 15 Flashcards

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Questions and Answers

What is the main difference between direct and alternating current?

Direct current is electricity that flows in only one direction; alternating current is electricity that reverses at regular intervals.

What is the force with which an electric current flows?

Voltage

What unit of measurement is used to describe the amount of current?

Ampere

How is power defined when dealing with electricity?

Power equals voltage times current (P=VI) Signup and view all the answers

What is the difference between a conductor and an insulator?

A conductor is material through which current flows easily; an insulator is material through which current does not flow easily. Signup and view all the answers

What term describes the amount an object hinders current flow, and what unit is used to measure this quantity?

Resistance; ohm Signup and view all the answers

What are three factors that affect the ease of current flow?

Type of material, diameter of conductor, length of conductor, temperature. Signup and view all the answers

If 5.0 C of charge flows through a wire in 0.50 s, what is the current (in amperes)?

10 A Signup and view all the answers

What is a superconductor?

A material that allows current to flow through it with no resistance at all. Signup and view all the answers

How can Ohm's law be stated mathematically?

V = IR Signup and view all the answers

What is an electrical device designed to add resistance to a circuit?

Resistor Signup and view all the answers

What are the three basic parts of a simple electric circuit?

Source of current, conductors, load. Signup and view all the answers

What is the difference between a closed circuit and an open circuit?

A closed circuit contains a complete path for electrons to flow; an open circuit has a gap that electrons cannot cross. Signup and view all the answers

What term refers to a dangerous situation in which electricity takes a 'short cut' through a circuit, avoiding the load?

Short circuit Signup and view all the answers

What two types of devices may be used to prevent circuits from overheating due to faulty wiring, overloads, or short circuits?

Fuses, circuit breakers Signup and view all the answers

In which type of circuit are the loads arranged so that electricity has to flow through each load one after another?

Series Signup and view all the answers

In which type of circuit are the loads arranged so that electricity is divided among the different loads?

Parallel Signup and view all the answers

Why might it be dangerous to replace a blown-out fuse with a fuse of larger capacity?

A larger fuse would not protect against an overloaded circuit and could allow more current to pass than the circuit can safely handle. Signup and view all the answers

What device produces light using a filament heated to a very high temperature by electricity?

Incandescent lamp Signup and view all the answers

Which type of light is more efficient: the incandescent lamp or the fluorescent lamp?

Fluorescent lamp Signup and view all the answers

What semiconductor devices are used to emit light?

Light-emitting diodes (LEDs) Signup and view all the answers

What simple device converts electricity to back-and-forth motion?

Solenoid Signup and view all the answers

What 19th century communication device used electromagnets to reproduce messages by means of audible clicks?

Telegraph Signup and view all the answers

What is a relay?

Electrical switch operated by an electromagnet. Signup and view all the answers

What device uses electromagnets to convert pulses of electricity into sound waves?

Loudspeaker Signup and view all the answers

What is the most important device for converting electricity into motion?

Electric motor Signup and view all the answers

List the three main parts of a simple AC motor and explain the purpose of each part.

Field magnet (provides a stationary magnetic field), armature (rotating electromagnet that aligns with the poles of the field magnet), slip rings (keep the wires from twisting as the armature turns). Signup and view all the answers

What is a group of electrochemical cells connected together as a single source of current?

Battery Signup and view all the answers

What is electromagnetic induction?

Ability of magnetism to convert mechanical motion into electrical energy. Signup and view all the answers

Study Notes

Electric Current

Direct current (DC) flows in one direction; alternating current (AC) reverses direction at regular intervals.
Voltage is the driving force behind the flow of electric current.
The amount of electric current is measured in amperes.

Power and Circuit Components

Power in electrical terms is defined as the product of voltage and current (P = VI).
Conductors allow current to flow easily, while insulators resist the flow of current.
Resistance quantifies how much a material hinders current flow, measured in ohms.

Factors Affecting Current Flow

Current flow is influenced by the material type, diameter and length of the conductor, and temperature.

Circuit Types

A closed circuit has a complete path for electrons to flow; an open circuit has a gap preventing flow.
Series circuits connect loads sequentially, while parallel circuits divide current among loads.

Safety Devices

Short circuits occur when electricity finds an unintended path, bypassing the load, potentially creating dangerous conditions.
Fuses and circuit breakers are safety devices that prevent overheating and circuit damage from overloads or faults.

Electrical Devices

Resistors add resistance to circuits; incandescent lamps produce light via heated filaments.
Fluorescent lamps are more energy-efficient than incandescent lamps.
Light-emitting diodes (LEDs) are semiconductors that emit light when current passes through.

Electromagnetic Devices

A solenoid converts electrical energy into back-and-forth motion.
The telegraph, an early communication device, used electromagnets to transmit messages audibly.
Relays are electrical switches operated by electromagnets, while loudspeakers use electromagnets to convert electrical pulses into sound waves.

Electric Motors and Batteries

Electric motors are key devices for transforming electrical energy into mechanical motion.
A simple AC motor consists of a field magnet, armature (rotating electromagnet), and slip rings (prevent twisting wires).
Batteries are collections of connected electrochemical cells that provide a current source.

Electromagnetic Induction

Electromagnetic induction is the principle of converting mechanical motion into electrical energy through magnetic fields.

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Description

Test your knowledge on key concepts from Physical Science Chapter 15 with these flashcards. Topics include the differences between direct and alternating currents, voltage, and the unit of current measurement. Perfect for quick revision!