Electricity and Conductors

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Questions and Answers

What role do free electrons play in a material's ability to conduct electricity?

They act as insulators.

They enable the transfer of electric charge. (correct)

They disrupt the flow of protons.

They create magnetic fields.

Which of the following correctly defines electrical resistance?

The amount of free electrons in a conductor.

The rate at which charge is flowing through a circuit.

The measure of voltage difference between two points.

A material's tendency to oppose the flow of electric charge. (correct)

What is the unit of measurement for voltage?

Watts (W)

Ohms (Ω)

Volts (V) (correct)

Amperes (A)

What happens when electrons move through a conductor?

They create an electric charge or current. Signup and view all the answers

Which materials are classified as good insulators?

Glass and rubber Signup and view all the answers

What is voltage often referred to as in its historical context?

Electromotive force (emf) Signup and view all the answers

Which statement about the particles in an atom is true?

Protons and electrons have opposite charges. Signup and view all the answers

What is the primary source of electricity generation mentioned?

Friction, induction, and chemical change. Signup and view all the answers

What is the value of one watt in relation to joules?

One joule per second Signup and view all the answers

Which of the following represents working power?

Kilowatt (kW) Signup and view all the answers

What type of power do resistive loads primarily use?

True or real power Signup and view all the answers

How is the power factor defined?

Ratio of working power to apparent power Signup and view all the answers

What is the significance of a power factor of 80 percent?

Only 80 percent of incoming power does useful work Signup and view all the answers

What does reactive power primarily require for operation?

A magnetic field Signup and view all the answers

What represents apparent power in electrical terms?

Kilovolt-amperes (kVA) Signup and view all the answers

What does the term 'load' refer to in an electric circuit?

An electric load that consumes electrical energy Signup and view all the answers

What causes voltage drop in wires carrying current?

Resistance or impedance Signup and view all the answers

Which type of electric current is characterized by electricity flowing in one direction?

Direct Current (DC) Signup and view all the answers

What is a key advantage of Alternating Current (AC) compared to Direct Current (DC)?

It can be distributed over long distances with low voltage drop Signup and view all the answers

What defines a series circuit?

A single path exists for current flow with elements in succession Signup and view all the answers

What does a current of 1 ampere represent in terms of electron flow?

6.24 x 10^18 electrons moving past a point in 1 second Signup and view all the answers

According to Ohm's Law, which equation represents the relationship between voltage, current, and resistance?

V = IR Signup and view all the answers

What unit is used to measure electrical power in a circuit?

Watt Signup and view all the answers

What unit is used to measure electrical resistance?

Ohms Signup and view all the answers

What describes a parallel circuit?

It allows loads to connect to the same voltage across separate branches Signup and view all the answers

According to Ohm's Law, what is the relationship between voltage, current, and resistance?

Current is directly proportional to voltage and inversely proportional to resistance Signup and view all the answers

What is the effect of increased resistance on current flow?

Decreases current flow Signup and view all the answers

Which statement about energy is correct?

Energy is the capacity to do work and exists in various forms Signup and view all the answers

Which scientist is credited with formulating Ohm's Law?

Georg Simon Ohm Signup and view all the answers

What defines a complete circuit for electric current to flow?

A source of voltage, a complete path, and a load Signup and view all the answers

What happens when too much electricity flows through a small conductor?

Heat is produced, possibly causing damage Signup and view all the answers

What is measured in amperes (A)?

The flow of electrical charge Signup and view all the answers

What is the function of a generator in a power station?

To convert mechanical power into electric power Signup and view all the answers

Which component of an electric motor remains stationary?

The stator Signup and view all the answers

How does an electric motor generate force?

Through the interaction of magnetic fields and electric current Signup and view all the answers

What is the main purpose of steam turbines in electricity generation?

To convert kinetic energy of steam to mechanical energy Signup and view all the answers

What is the role of the rotor in an electric motor?

To spin and create a changing magnetic field Signup and view all the answers

Which part of the power distribution grid is responsible for transmitting electricity from power plants?

National Grid Corporation of the Philippines Signup and view all the answers

What do steam turbines use to rotate the shaft connected to the generator?

Moving fluid such as steam Signup and view all the answers

In an electric generator, what does the stator do?

Receives the magnetic field produced by the rotor Signup and view all the answers

What is the primary function of a substation in an electrical system?

To transform voltage levels Signup and view all the answers

Which type of transformer is used to convert high voltage to low voltage?

Step-Down Transformer Signup and view all the answers

What is the voltage that a power plant typically generates?

25,000 V Signup and view all the answers

What characteristic distinguishes a service transformer from other types of transformers?

It provides final voltage transformation for customer use. Signup and view all the answers

Which of the following describes three-phase power supply?

It delivers power at a steady, constant rate. Signup and view all the answers

What happens at a distributing substation?

Voltage is stepped down for use by customers Signup and view all the answers

How does a step-up transformer function?

It increases voltage for transmission Signup and view all the answers

What is a common application for single-phase power supply?

Residential lighting and heating Signup and view all the answers

Study Notes

Electricity

Electricity is the movement of electrons
Electricity is a form of energy generated by friction, induction, or chemical changes. It also has magnetic, chemical and radiant effects.
Electrons are in motion
Atoms are made up of electrons, protons, and neutrons
Electrons have a negative charge
Protons have a positive charge
Neutrons have no charge
The number of protons, neutrons, and electrons tell us what material it is.

Conductors and Insulators

Conductors allow electrons to pass meaning they can conduct electricity.
Metals are good conductors, e.g., copper
Materials without free electrons are insulators, e.g., rubber and glass, silicone rubber.

Current

Current is the rate at which electrons flow through a point in a circuit.
If the flow of electricity is excessive in a small conductor, heat is produced which may cause problems or the burn of the insulator
Current is measured in amperes (A)
Current means that 1 Coulomb of electrons (6.24 x 10¹⁸ electrons) passes a single point in the circuit in one second.

Voltage

Defined as the pressure from an electrical circuit’s power source that pushes charged electrons through a conducting loop.
Enables electricity to do work, like lighting a bulb.
Measured in Volts (V)

Resistance

Resistance is a measure of the opposition to current flow in an electric circuit.
Resistance is the friction or opposition to the flow of current by the wires and transformers.
Higher the resistance, lower the current.
Overheating is an issue often associated with high resistance.
Resistance is measured in Ohms (Ω).

Ohm's Law.

Ohm's law describes the relationship between voltage, current, and resistance in an electric circuit.
Ohm's law states: V= I×R, where:
- V = voltage
- I = current
- R = resistance

Types of Circuits

Series Circuit: A single path for current flow, with components connected in sequence. The total voltage and resistance are the sum of each respectively.
Parallel Circuit: Multiple paths for current flow. Components are connected across the same voltage, constituting separate circuits.

Energy

Energy is the capacity for doing work.
Energy exists in various forms: potential, kinetic, thermal, electrical, chemical, and nuclear.
Energy cannot be created or destroyed.
The SI unit for energy is the Joule (J).

Power

Power is the rate of transfer of energy over time.
Power is measured in watts (W) (or joules per second).
Electrical power is equal to voltage times current (P=IV).

Electric Power Generation

Most electricity is produced using steam turbines.
Steam turbines convert the kinetic energy of a moving fluid to mechanical energy.
Steam turbines consist of a series of blades mounted on a shaft.
Steam is forced against the blades and forces the shaft to rotate, powering a generator to create electricity.

The Electrical Grid

Electricity from a plant travels through a system called the power distribution grid.
The NGCP is responsible for operating, maintaining, and developing the transmission system of the electricity grid.
The grid coordinates the supply and demand of electricity.
The grid delivers electricity throughout the different parts of the Philippines, namely Luzon, Visayas, and Mindanao.

Transformers

Transformers transfer electric energy from one alternating-current circuit to one or more other circuits.
Transformers can either increase or reduce the voltage, known as stepping up or stepping down.
A transformer increases voltage via a higher number of windings in the secondary coil; transformers reduce voltage via a lower number of windings in the secondary coil.
Transformers are essential for electricity transmission over long distances.

Substations

Substations are part of the electrical generation, transmission, and distribution system.
Substations transform high voltage to low and vice-versa
Substations are responsible for performing important functions in the electricity distribution system.
Service transformers provide final voltage transformation.
Serve as distribution transformers in a system.

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Description

This quiz explores the principles of electricity, including the movement of electrons and the differences between conductors and insulators. Understand the properties of current and how materials interact with electrical energy. Test your knowledge on these fundamental concepts in electricity.