Answer:
-6.4x10⁻¹⁹ C
Explanation:
The elementary charge of one electron is -1.60x10⁻¹⁹C, so each electron has its charge, and a sample with more than one electrons will have a multiple of its charge, which is proportional to the number of electrons. So, if the oil droplet had 4 electrons, thus the charge will be four times the elementary charge:
4*(-1.60x10⁻¹⁹) C = -6.4x10⁻¹⁹ C
26. a megagram = 10⁶ grams while a kilogram = 10³ grams, so the megagram is bigger
28. a mililiter = 10⁻³ liters while a microliter = 10⁻⁶ liters, so the mililiter is bigger
36. 1 meter is equal to 100 centimeters, so the decimal moves right 2 places
37. 1 micrometer is equal to 0.001 milimeters, so the decimal moves left 3 places
38. 1 centimeter is equal to 0.00001 kilometers, so the decimal moves left 5 places
39. 1 micrometer is equal to 10⁻¹² megameters, so the decimal moves left 12 places
40. 1 kilometer is equal to 100000 centimeters, so the decimal moves right 5 places
