Power, Work, Energy, Capacitance, and Magnetism

Which example best represents energy consumption over time?

A light bulb using 60 watts for two hours

In photovoltaic cells, what is a "hole"?

An absence of an electron that behaves like a positive charge

Why is 1 horsepower often compared to 746 watts?

Because it standardizes both mechanical and electrical power

Why are thermocouples valuable in aviation applications?

They generate current without any external power supply

Why are solar cells used in spacecraft and satellites?

They can operate without moving parts and use abundant sunlight

What is the historical importance of the watt as a unit?

It unified electrical and mechanical measurements of energy transfer

Why did James Watt compare horse strength to his steam engine?

To create a standard for measuring mechanical power

What is the key difference between power and energy?

Power is a rate, while energy is a total amount

Why is power considered the "rate of doing work" in both mechanical and electrical systems?

Because it measures energy transfer over time

Why are piezoelectric materials widely used in microphones and sensors?

They can transform sound vibrations into electrical signals

Why are kilowatt-hours more practical than joules for utility companies?

Because they represent larger, more usable amounts of energy

Which aviation measurement commonly uses thermocouples?

Cylinder head temperature and turbine inlet temperature

Why is power considered additive in both series and parallel circuits?

Because the total power equals the sum of each resistor's power dissipation

Why are piezoelectric effects used in both sensors and speakers?

Because they can convert mechanical input into electrical output, and vice versa

Why is energy described as "the ability to do work"?

Because it can be stored, transferred, or converted into motion or heat

In a battery, why do electrons flow when a wire connects the terminals?

To balance the electrical charge difference between the two metals

Which source of electricity depends on chemical reactions between dissimilar metals?

Chemical

What scientific principle allows thermocouples to produce voltage from heat differences?

Seebeck effect

Why is total power easy to calculate in circuits?

Because power is always added across each device regardless of configuration

Which unit is most commonly seen on electric bills to represent energy use?

Kilowatt-hour

What does one watt represent?

One joule of energy used in one second

Why are semiconductors like silicon used in solar cells?

They easily allow photons to excite electrons into motion

What key principle connects all sources of electricity—pressure, chemical, thermal, and light?

Each source produces electrical energy by freeing or moving electrons

Which best describes the function of piezoelectric materials?

They produce electrical voltage when pressure is applied

In an electrical motor, what does a horsepower rating represent?

The equivalent mechanical work output compared to a horse