6837874
Description
Flashcards by Ahmed Almohammed, updated more than 1 year ago
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Created by Ahmed Almohammed
over 7 years ago
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| Question | Answer |
| In what form does the energy from the sun reach the earth as? | Almost all energy on Earth comes from the Sun, mostly in the form of high-energy, short-wave radiation. |
| What does the laws of thermodynamics describe and what does "thermo" and "dynamic" mean? | The laws of thermodynamics describe the ways in which energy moves. The word "Thermo" relates to heat, and "Dynamic" refers to movement. |
| What are the laws of thermodynamics? | 1- Energy can neither be created nor destroyed, it can only change form. 2- Heat can flow from a high-temperature region to a lower-temperature region. 3- As temperature approached absolute zero, particle motion approaches a minimum. |
| Why do the brake disks of racing cars become red hot? | The brake disks of racing cars can become red hot as a result of a transfer of energy (Kinetic energy to Heat energy) |
| What happens to the energy when it is transformed from kinetic into heat energy in the break pads and disks of a racing car? | This energy (Heat energy) then radiates into the air as infrared radiations or heats up the surrounding air as the disks cool down. |
| What form of radiation do plants use to carry out photosynthesis? | Plants use the energy in short-wave solar radiation to carry out photosynthesis, creating sugars (high in energy) from carbon dioxide and water. |
| How does a fridge moves heat energy from inside to outside the fridge? | The coolant changes from liquid to gas in the expansion valve. It absorbs heat from the food inside the fridge and is then compressed so that it is at a high pressure. The coolant gives out this heat at the back of the fridge and cools back to liquid. |
| Why do the coils at the back of a fridge get really hot? | The coils at the back of a fridge will get hot because of the energy losses that are occurring. |
| Why is it that more heat is released to the outside of the fridge than is removed from the inside? | More heat is released to the outside of the fridge than is removed from the inside, because some energy is wasted and released as part of the process of moving energy from cold to warm. |
| What is the definition of temperature relating to the third law? | Temperature is a measure of the energy of motion of the particles that make up solids, liquids and gases. |
| What is the absolute zero? | Absolute zero is a theoretical limit that is impossible to actually reach. It's -273.15*C As something is cooled towards absolute zero, everything around it will be warmer , and will keep giving it energy. |
| Why is it that energy transformations are never 100% efficient? | Energy transformations are never 100% efficient as some energy is always lost as heat energy at each step. |
| How do we calculate the energy efficiency of any process? | |
| How do the laws of thermodynamics show that we will never be able to produce 100% energy efficient processes? | At every energy transformation, energy is lost as heat. This is a consequence of the second law of thermodynamics. All energy transformations are the same: at each transformation, some energy is lost as heat. |
| What is the average excrete of a person? | The average person excretes about 350g in a day. |
| What is the producer? | The producer is usually a green organism that gets its food through photosynthesis using solar energy, and is eaten by consumers. |
| What is the consumer? | The consumer is an organism that eats other living organisms, either plants or animals(Sometimes the producers) |
| How does your weight remain constant? | If your activity uses up the same amount of energy contained in the food you eat, your weight remains constant. |
| what happens when a solid is cooled further? | As a solid is cooled further, its particles vibrate less and less. |
| What happens when you go from gas to solid to liquid? | As you go from gas to solid to liquid, the particles in each state have less movement. |
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