Yr 9 Science Half Yearly Exam Flashcards

Flashcards based on the Energy Outcomes lecture notes.

What is energy?

The ability to do work.

What is energy considered to be?

A property of a system.

What does the Law of Conservation of Energy state?

Energy cannot be created or destroyed, only transformed.

How does positive and negative work affect the energy of a system?

Positive work adds/increases energy, negative work takes away/decreases energy.

Work done equals energy transferred, what is the formula for Work done?

Force x distance.

What does an open system exchange with its surroundings?

Transfers both energy and mass.

What does a closed system exchange with its surroundings?

Transfers only energy.

What does an isolated system exchange with its surroundings?

Exchanges neither energy nor mass.

What is the formula for Gravitational Potential Energy (GPE)?

mgh

What is the formula for Kinetic Energy (KE)?

1/2mv^2

Name types of kinetic energy.

Mechanical, Electrical, Thermal, Radiant, and Sound.

Name types of potential energy.

Chemical, Nuclear, Gravitational, and Elastic.

In a 100% efficiency environment, what is the relationship between gravitational height and velocity?

Gh = 1/2v^2 (in 100% efficiency environment).

What is the first step in using any energy diagram

Define initial and final points in time.

What basic shapes are used in an energy cube model?

Rectangles showing energy in different states and how energy cubes move from rectangles to show the energy transfers

How does an energy flow diagram represent a system and energy transfers?

Representing the system and its surroundings, using arrows to show energy transfers.

Where does the energy stay in an energy flow diagram?

Energy Stored

What are the primary components of a work energy bar chart?

Multiple time frames, amount and type of energy in system for each time frame

What is the formula for efficiency?

Useful energy output / total energy input OR useful power output / useful power input.

What happens to any unintended energy within an energy system?

Energy is wasted

For a lamp, what is an example of useful output energy?

Light

For a lamp, what is an example of waste energy?

Heat

What does energy evaluate in a system?

Evaluating the performance of machines and systems.

What is renewable energy?

Replenished within a realistic amount of time so that it never runs out.

Give examples of renewable energy sources?

Wind, solar, hydro, geothermal, biogas, biomass, gravity.

Give examples of Non-Renewable energy sources?

Oil, nuclear, petrol, coal, natural gas, fossil fuels.

What is dispatchable power?

Continuous supply that can be turned on/off.

What are the main forms are dispatchable power?

Hydro (gravitational), hydrogen, geothermal, biogas, biomass, hydroelectric

Can intermittent power be controlled?

Humans don’t have control over it

What the the main forms of intermittent power?

Solar, Wind

What is the primary material used in nuclear energy generation?

Uranium

What is a disadvantage of nuclear reactors?

Lots of radiation

Describe the process of how a wind turbine works.

Wind pushes turbine, electrical energy is stored, wind continues moving slower.

what is the first step of how a wind turbine works?

Wind pushes turbine causing it to spin

When did fossil fuels begin forming (approximately)?

360 to 286 million years ago.

What are the four defining factors that determined the type of fossil fuel formed?

Organic matter, temperature, time, and pressure conditions.

What are the three main types of fossil fuels?

Coal, oil, and natural gas.

Why are fossil fuels generally preferred over other forms of energy?

High energy density.

Name some products of fossil fuels

Electricity, plastics, cosmetics, and some medicines.

What are areas of oil concentrations called?

Reservoirs

What is the most common way to extract oil?

Drilling a well.

Give some examples of some products which oil can refined into

Gasoline, diesel, jet fuel, asphalt

Watts =?

Joules per second.

What is a megawatt (MW)?

A million watts.

What is a gigawatt (GW)?

A thousand megawatts or a billion watts.

How efficient is generating electricity?

Generating electricity is very inefficient, as lots of energy goes to heat.

How is electricity generated?

Coal is burnt, heats up water, water turns to steam, pressurised steam turns turbine, turbine generates electricity.

When electrial energy is not needed it is used to run pumps that pump water from lower dam storage to higher dams to use at peak times, what happens after this?

The water then later falls against a turbine, causing it to spin (pumped storage).

The following statement is describing which term: Materials that conduct electricity resist the flow to some degree

Resistance

Which type of wire has low resistance?

Electrical wires

How does a ligh globes volatage impact resistance?

Increasing resistance the higher the voltage (curved on a line graph).

How does a standard resistors volatage impact resistance?

Same resistance with different voltages (have a straight line on the graph)

What are the only 2 things you can change in a circuit

Voltage and Resistance

What things can change resistance?

Length of conductor, cross-sectional area of conductor, temperature, and type of material.

What happens after heating up water when generating electricity?

Water turns to steam

What type of work decreases energy?

Negative work

What is the ability to do work?

Energy

Work Done = ?

Amount of energy transferred

What is gravitational height represented by?

Gh

What is a good tip when using energy diagrams?

Simplify everything

Efficiency = ?

Useful energy output / total energy input

What is the main 'obstacle' that devices need to overcome, in order to become 100% efficient?

Heat

Energy evaluates the _ of machines and systems

Performance of machines and systems

Renewable energy can be replenished within a _

Realistic amount of time

Oil, nuclear, petrol, coal, natural gas are all types of what?

Fossil fuels

After uranium is used to release energy, to heat up water, water turns to steam, pressurised steam turns a turbine, what occurs next?

Turbine generates electricity

Coal, a type of fossil fuel is formed by what undergoing pressure and heat?

Plants, trees and ferns

Oil, a type of fossil fuel is formed from what undergoing pressure?

Small organisms

How is natural gas formed in reference to other fossil fuels?

Similar to oil but with more heat and pressure

Oil can be called or

Petroleum or crude

Oil is made up of: _

Hydrogen and carbon, sulphur, nitrogen, oxygen

MW stands of _

MegaWatt

GW stands of _

GigaWatt

Components such as light globes and resistors have _ resistance

High resistance

What is the charge of a lattice of particles that slowdown electrons?

Positive

Electrical Energy =

𝑉𝐼𝑡

Temperature change is represented as?

∆𝑇

how does work affect the the energy of a system

Negative work decreases, positive work increases it

What evaluates the performance of machines and systems?

Efficiency

Where is electrical energy stored, inside a wind turbine?

A battery

Where did plants and animal decompose to form fossil fuels?

The bottom of the sea under minerals

Name the ways to extract oil?

Seismic, rock core sampling and surveying

Which system is hardest to create, open, closed or isolated?

Isolated system

_ power is a form of dispatchable power

Hydro

_ = Joules per second

Watts

What type of system transfers energy and mass?

Open