In mammals, the eardrum transmits sound waves to three small bones, which transmit the waves to fluid waves within the cochlea. where are the three small bones located?

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.

well, i believe that the answer is 2. : 3

energy per photon is e = h*c / λ  

e = 6.63*10^-34 * 3*10^8 / 6*10^-7 j = 3.315*10^-19 j  

nr. of photons = 10j / 3.315*10 = ^-19 j per photon = 3.02*10^19 photons