physics Flashcards
energy
The ability to do work
Unit of energy
Joules (J)
Forms of energy
Types of energy (chemical, mechincal, potential, etc)
Source of energy
Where is the energy being acquired from (sun, battery, motion, etc)
Internal Energy
Total Kinetic and Potential energy of all molecules in a material. Microscopic and within a body
The hotter the body the _____ the internal energy
Greater
Thermal energy
Form of energy which is always in motion from a body at higher temp to a body at a lower temp
Heat energy converts to what when a body absorbs it
Internal energy and NOT HEAT ENERGY
How does thermal energy affect a particles KE and PE
Increase in speed (KE) and change in state of matter (PE)
Mechanical energy
Energy an object possess due to its motion or position
2 main types of mechanical energy
Kinetic and Potential
Kinetic energy
Energy which is possessed by moving objects
Kinetic energy can also be expressed as
Amount fo work done
Potential energy
Energy stored in am object due to change in position, shape or state of matter
Conservative force
Force where the work done does not depend on the path travelled by the body
Types of forces of conservative forces (examples)
Electrostatsic
Restoring
Gravitational force
2 main types of PE
Gravitational PE and Elastic PE
Real life application of conservative force
Moving upwards and moving sideways
Moving sideways takes into consideration the conditions of path tarveling
whereas moving upwards doesnt require focus on the path taken rather its dependant on work done
2 types of energy sources
Primary and secondary
Primary source
Natural source, no processing or refind, energy must occur naturally in the source
eg of primary source
thermal energy, chemical energy, nucluer energy
secondary source
Artificially manufactured and has to be created by humans, useful transformations of the primary sources into energy
renewable energy source
Easily replenished
Generated from natural sources
Less harmful to nature
Won’t run out
Little to no waste
Dependant on weather
Installation cost is super high, but maintenance is cheaper
Has a replenishment rate which humans do not follow
Eg of renewable energy
Solar energy, hydroelectric energy
Non renewable energy sources
Cant be easily replenished
Harmful to the environment
Amount of energy generated is very high compared to renewable
Found in abundance
Construction of power plants is very easy
eg of non-renwable sources
Fossil Fuels, Nuclear Energy
Impact of Renewable and non renewable Energy on climate Change
Reewnable energy posess little to no impact and renewable sources don’t release GHG emissions and reduce dependency on fossil fuels
Non renewable energy has a negative impact are burning fossil fuels releases large amount of GHG emissions which traps heat and increases global temp
ecological footprint - renewable and non renewable energy sources
Renewable energy sources reduce ecological footprint while non renewable increase the ecological footprint
Law of conservation of energy
energy can neither be created nor destroyed but can only be transformed from one form to another
Whenever there is an energy transformation
There will always be energy degradation
Energy degradation
Useful energy is transformed into a useless form of energy. The total amount of energy remains the same, but it is just in different forms of energy
Gases which absorb IRR and are essential to existence
Carbon Dioxide
Methane
Water vapour
Nitrous oxide
Greenhouse effect
Gasses which absorb IRR with higher wavelengths can’t retain them forever and eventually, they release them into the atmosphere. This increase global temp and causes global warming
Advanced GH effect
Increased methane and carbon dioxide which traps more heat and increase global temp even more
Temperature
Measure of the average random kinetic energy of particles in a system
Random KE
No fixed direction, speed or velocity of motion
Heat energy is proportional to
Mass and change in temp
Specific heat capacity
Amount of heat energy required to change the temp of 1kg of substance by 1 degree celsius
Melting point
Constant temp at which a solid completely transforms into the liquid state
Boiling Point
Constant temp at which a liquid completely transforms into the gaseous state
Latent Heat
Amount of heat energy required to convert 1kg of substance from one state to another
Latent heat of fusion
Amount of heat energy required to convert 1kg of solid to liquid state at a constant temp
Latent heat of vaporisation
Amount of heat energy required to convert 1 kg of liquid to gaseous state completely at a constant temp
Scale of temp
Kelvin, Celsius, Fahrenheit
Conduction
Heat transfer mechanism in which the particles vibrate vigoursly and collide with neighbouring particles. They do not get displaced and remain in their position
Includes direct physical contact
Which substances is conduction used for with example
For solids
eg - metal pot warming when placed over gas stove
Convection
Heat transfer mechanism in which the particles of a substance get displaced from their positions
Based on different in specific heat capacity
Which substance is convection used for with example
Fluids (Gas + liquid)
Eg - Hot air from heater warming your room and cold air from ac cooling your room
Radiation
Heat transfer mechanism which requires no medium for heat transfer. Heat is transferred in the form of electromagnetic waves
Example of radiation
Sun warming your skin on a sunny day
Consequences of Heat Transfer
Expansion/Contraction of materials when heated or cooled
Heat transfer can cause substances to change phases such as melting, freezing or vaporisation
Heat transfer can initiate or accelerate chemical reactions by providing the required activation energy
Thermal expansion
The tendency of materials to expand or contract in response to changes in temperature
Application of thermal expansion
- Engineering Structures - Thermal expansion is used in designing structures like bridges and railways to keep in mind its expansion during summer and prevent damage to the structure
- Electronics - Components in electronics are designed considering thermal expansion to prevent cracking or damage due to temperature changes.
