Electricity And Magnetism Flashcards
Can a changing magnetic field cause an electric current?
Yes. For example, electric generators use this principle to generate electricity by rotating a turbine in a magnetic field.
What causes a magnetic field?
The moving electrical charges or some other change in electric currents.
What are the basic types if circuits?
Series circuit: +battery-> light bulb->-battery
Parallel circuit: +battery-{--light_light-_}->-battery
What is the most fundamental law about energy?
It can be neither created nor destroyed, it can only change forms, and the total amount of energy in a closed system must remain constant.
What is mechanical energy?
The total of the potential (energy due to position) plus kinetic (energy due to movement) energy
Potential energy
Energy based on position or condition rather than movement. Coiled spring has potential energy. Also the chemical energy released during a reaction is the potential energy stored by the molecules involved in the reaction
Kinetic energy
Energy possessed by a body because of its motion. Heat is kinetic energy on molecular level, as molecules speed up and randomize.
E=mc^2
Energy can also take the form of mass. Mass and energy are interchangeable. In nuclear reactions, energy is released because some of the mass in the nuclei is converted is converted to energy.
What is work?
The force times the distance over which the force is applied. Simple machines ands levers don’t reduce the amount if work, they just spread the force over wider area.
What are the three ways that heat is transferred?
By conduction, convection, and radiation
What is heat transfer via conduction?
Conduction requires direct contact. The fast moving particles collide with those of the cold object, thereby increasing the speed of the particles of the cooler object. Burn hand on stove
What is heat transfer via radiation?
The transmission of energy through rays, waves, and particles. Sunlight warming you up
What is heat transfer via convection?
The transfer of heat through gas or liquid by circulating currents that move from one region to another. Convection currents in earth’s mantle moved the tectonic plates.
Photon
A subatomic particle having a zero mass and no electrical charge. Light cones in discrete packets if photons, particles of light.
Spectroscopy
A sub-discipline of physics concerned with the interactions between matter and radiation. Electrons absorb, bump up, bump down, then release photons again. Each element had its own unique set of energy levels tat can be seen as spectral lines. Scientists use this to identify the chemical composition.
