sound waves, energy resources and changes of state Flashcards
what is the frequency range for human hearing?
20 - 20 000 Hz
describe an experiment to investigate the speed of sound in air
- connect 2 microphones to an oscilloscope
- set the frequency of a signal generator to 1kHz
- adjust the settings of the oscilloscope so that both waves can be seen at the same time
- slowly move one microphone away from the speaker until the two waves are aligned on the display as they are exactly one wavelength apart
- measure the distance between the microphones with a tape measure
- multiply the frequency (1kHz) by the wavelength that you have just measured to find the wave speed
how do you find the frequency of a wave from an oscilloscope?
- the x axis is time
- check the time between each division as this is adjusted on a scale to get a clear, readable display of the wave
- measure the time period by counting how many divisions there are in one complete cycle of a wave and multiply this by the time of each division
- frequency is 1 divided by the time period
how does the pitch of a sound relate to its frequency?
the higher the frequency, the higher the pitch
how does the loudness of a sound relate to its amplitude?
the greater the amplitude, the louder the sound is
describe the energy transfers involved in nuclear reactors
energy is transferred from nuclear energy stores to thermal energy stores by heating, then mechanically to kinetic energy stores, and finally transferred electrically through the national grid
what are the advantages and disadvantages of nuclear power?
advantages: doesn’t produce greenhouse gases
disadvantages: risk of leaks of radioactive material, radioactive waste is hard to dispose of and it is expensive to build and maintain nuclear reactors
describe the energy transfers involved in wind farms
kinetic energy > electrical energy
disadvantages and advantages of wind farms
advantages: cheap to run, wind is free and renewable and no polluting waste
disadvantages: spoil the view, wind turbines don’t produce that much energy individually so many are needed and they can be noisy
describe the energy transfers involved in geothermal power
thermal energy > kinetic energy > electrical energy
disadvantages and advantages of geothermal power
advantages: renewable, reliable and low environmental impact
disadvantages: not many places are suitable, harmful gases can be released from underground
describe the energy transfers involved in solar power
nuclear energy > light and thermal energy > electrical energy
a and d of solar cells
a: no waste or greenhouse gases and renewable
d: unreliable
describe solar panels
energy from the sun can be absorbed by black pipes that carry water so the water heats up
describe cooking with solar power
a curved mirror focuses the sun’s light. this is used in a solar oven
