To analyze the experiment used to determine the properties of an electron. in 1909, robert millikan performed an experiment involving tiny, charged drops of oil. the drops were charged because they had picked up extra electrons. millikan was able to measure the charge on each drop in coulombs. here is an example of what his data may have looked like.
drop charge (c)
a 3.20 x 10^{-19}
b 4.80 x 10^{-19}
c 8.00 x 10^{-19}
d 9.60 x 10^{-19}
based on the given data, how many extra electrons did drop c contain?

Considering the data, drop C contained 5 extra electrons.

Explanation:

Robert Millikan and his colleague Harvey Fletcher puplished in 1911 a work in which they discribed an experiment that lead to the measurement of the elementary charge (e). These scientists determined that each electron has a charge equal to 1.60217662 × 10⁻¹⁹ coulombs.

Considering that each oil drop is neutral, the charge observed is due to extra electrons. Therefore, in order to determine the number of extra electrons (n) we need do divide the drop charge C by the elementary charge (e):

n = 8.00x10⁻¹⁹/1.60217662 × 10⁻¹⁹

n = 5 extra electrons.

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error