What was the first substance discovered to exhibit electrical properties?
- Iron
- Amber
- Gold
- Silver
Correct Answer: Amber
Correct Answer Explanation: The book notes that Thales of Miletus first described the electrical properties of amber in 600 BC. When rubbed, amber attracts and repels light objects, demonstrating its electrical properties.
Which animal was known for its ability to emit electric impulses in ancient times?
- Electric Eel
- Torpedo Fish
- Octopus
- Shark
Correct Answer: Torpedo Fish
Correct Answer Explanation: The book mentions the torpedo fish, highlighting that its ability to emit electric impulses was known even in ancient times. This predates our understanding of electricity as a force.
What was the first attempt to store electricity?
- The Voltaic Pile
- The Leyden Jar
- The Crown of Cups Battery
- The Simple Current Detector
Correct Answer: The Leyden Jar
Correct Answer Explanation: Invented in 1740, the Leyden Jar was a pivotal development in understanding and storing electricity. It utilized glass, tinfoil, and sulphuric acid to hold an electrical charge.
Who proved that lightning is a form of electricity?
- Alessandro Volta
- Benjamin Franklin
- Hans Christian Ørsted
- André-Marie Ampère
Correct Answer: Benjamin Franklin
Correct Answer Explanation: Benjamin Franklin’s famous kite experiment in the 1750s conclusively demonstrated that lightning is a form of electricity. This groundbreaking discovery revolutionized our understanding of this powerful force.
What type of electricity is produced by chemical reactions between metals and liquids?
- Frictional Electricity
- Voltaic Electricity
- Electro-Magnetic Electricity
- Static Electricity
Correct Answer: Voltaic Electricity
Correct Answer Explanation: Discovered in 1790, voltaic electricity, named after Alessandro Volta, is generated through chemical reactions involving metals and liquids. This discovery led to the invention of the first batteries.
Which of these is NOT a method of generating electricity as described in “Electricity for Boys”?
- Frictional Electricity
- Voltaic Electricity
- Wind Power
- Electro-Magnetic Electricity
Correct Answer: Wind Power
Correct Answer Explanation: While wind power is now a significant source of electricity, the book focuses on the three primary methods known at the time: frictional, voltaic (chemical), and electro-magnetic. Wind power was not widely explored until later.
Who discovered the magnetic effect of electricity?
- Alessandro Volta
- Hans Christian Ørsted
- André-Marie Ampère
- Michael Faraday
Correct Answer: Hans Christian Ørsted
Correct Answer Explanation: Hans Christian Ørsted’s discovery in 1820 that electricity creates a magnetic field laid the foundation for the development of motors and dynamos. This groundbreaking finding revolutionized our understanding of the relationship between electricity and magnetism.
Who proposed the idea of a motor and a dynamo powered by electromagnetism?
- Benjamin Franklin
- Michael Faraday
- André-Marie Ampère
- Alessandro Volta
Correct Answer: André-Marie Ampère
Correct Answer Explanation: André-Marie Ampère, building upon Ørsted’s discovery, conceptualized the idea of motors and dynamos powered by electromagnetism. This crucial insight paved the way for the development of electrical machinery.
What is the standard unit of measurement for electrical resistance?
- Volt
- Ampere
- Watt
- Ohm
Correct Answer: Ohm
Correct Answer Explanation: The book introduces the concept of resistance, the opposition to the flow of electrical current. Georg Simon Ohm defined this resistance and the standard unit of measurement, the ohm, which is used to quantify this opposition.
What is the earth’s magnetic field similar to?
- A compass needle
- A bar magnet
- A Leyden Jar
- A battery
Correct Answer: A bar magnet
Correct Answer Explanation: The book explains that the Earth is a giant magnet with a north and south magnetic pole, and magnetic lines of force flow between them. This is similar to the magnetic field produced by a bar magnet.
What are the best materials for making magnets?
- Silver and copper
- Iron and steel
- Aluminum and zinc
- Gold and platinum
Correct Answer: Iron and steel
Correct Answer Explanation: The book highlights that iron and steel are the best materials for making magnets. Other metals, like sulfur, zinc, bismuth, antimony, gold, silver, and copper, are non-magnetic.
What is NOT a characteristic of electromagnets?
- Created by winding a wire coil around a core of iron
- Energized only when a current flows through the coil
- They are permanent magnets
- Can be used in motors and dynamos
Correct Answer: They are permanent magnets
Correct Answer Explanation: Electromagnets are temporary magnets, meaning they only generate a magnetic field when a current flows through the coil. This differentiates them from permanent magnets, which retain their magnetism without the need for an electric current.
What is the principle behind the action of a dynamo?
- Electrostatic induction
- Electromagnetic induction
- Frictional electricity
- Voltaic electricity
Correct Answer: Electromagnetic induction
Correct Answer Explanation: The book explains that the action of a dynamo relies on the principle of electromagnetic induction. This phenomenon, discovered by Faraday, involves moving a conductor through a magnetic field, which then creates an electrical current.
What is a Leyden Jar also known as?
- A capacitor
- An accumulator
- A voltameter
- A battery
Correct Answer: A capacitor
Correct Answer Explanation: The Leyden Jar is essentially a capacitor, a device that stores electrical energy. It stores charges on the tinfoil coating, separated by the glass dielectric, allowing it to hold an electrical charge.
What is the unit of measurement for the intensity of an electric current?
- Volt
- Ampere
- Watt
- Ohm
Correct Answer: Ampere
Correct Answer Explanation: The book explains that the intensity of an electric current is measured in amperes. One ampere is defined as the amount of current that deposits 0.001118 grains of silver per second in a standard solution of silver nitrate.
What is voltage a measure of?
- The rate of flow of electrical current
- The electrical potential difference between two points
- The opposition to the flow of electrical current
- The amount of electrical energy stored
Correct Answer: The electrical potential difference between two points
Correct Answer Explanation: Voltage is defined as the electrical pressure required to move one ampere of current through one ohm of resistance. It is a measure of the electrical potential difference between two points, representing the “push” or force that drives the flow of electrical current.
What is the unit of measurement for electrical power?
- Volt
- Ampere
- Watt
- Ohm
Correct Answer: Watt
Correct Answer Explanation: Watts are a measure of electrical power, representing the rate at which electrical energy is transferred or used. One watt is equal to one volt multiplied by one ampere.
What is NOT a type of battery mentioned in “Electricity for Boys”?
- The Voltaic Pile
- The Crown of Cups Battery
- The Accumulator Battery
- The Leyden Jar
Correct Answer: The Leyden Jar
Correct Answer Explanation: While the Leyden Jar stores electrical energy, it is not classified as a battery. The book highlights the Voltaic Pile, the Crown of Cups Battery, and the Accumulator Battery as specific types of batteries that produce electricity through chemical reactions.
What is an electrolyte?
- A conductor that allows electricity to flow through it
- A substance that produces electricity through chemical reactions
- A device that measures the strength of an electric current
- A type of battery
Correct Answer: A conductor that allows electricity to flow through it
Correct Answer Explanation: Electrolytes are substances that conduct electricity through the movement of ions. These are often liquid solutions, allowing the flow of electricity between electrodes.
What is NOT an example of an early electrical device mentioned in “Electricity for Boys”?
- The Electric Bell
- The Annunciator
- The Burglar Alarm
- The Radio
Correct Answer: The Radio
Correct Answer Explanation: The book focuses on early electrical inventions, including the Electric Bell, Annunciator, and Burglar Alarm. While the radio was a later development, these earlier devices highlight the ingenuity and progress in harnessing electricity for various purposes.
What is the main takeaway from “Electricity for Boys”?
- Electricity is a powerful force with numerous applications
- The book is a comprehensive guide to the early world of electricity
- The book encourages a hands-on approach to learning about electricity
- All of the above
Correct Answer: All of the above
Correct Answer Explanation: “Electricity for Boys” is a comprehensive guide to the early world of electricity, encouraging a hands-on approach to learning about this powerful force. It highlights the numerous applications of electricity and its potential to revolutionize various aspects of life.