Ajoule is an amount of energy, and a watt is a rate of using energy, defined as 1 w = 1 j / s. how many joules of energy are required to run a 100 w light bulb for one day?

coal has about 30e6 j of energy per kg, but a power plant can only use 30% of this energy to make electricity (i. e., it is 30% efficient). how many kilograms of coal have to be burned to light a 100 w light bulb for one day?

Select light for the type of wave, adjust the wavelength so that the light is red, and increase the amplitude of the light to the max. then, select the start button at the source location to begin producing the waves. light is a form of electromagnetic wave, containing oscillating electric and magnetic fields. the wave amplitude detector mentioned above shows how the electric field oscillates in time at the location of the probe. the amplitude of the wave at the location of the probe is equal to the maximum electric field measured. how does the amplitude of the wave depend on the distance from the source?