Question

In Millikan's experiment, the charge on each drop of oil was measured in coulombs. Imagine the same experiment, but with charges measured in a fictitious unit called a zeet (Z).

Drop Charge (Z)

A 1.77×10−14

B 4.13×10−14

C 4.72×10−14

D 5.31×10−14

E 7.67×10−14

What is the charge on an electron in zeets?

Express your answer in zeets using two significant figures.

Answer 1

The charge on the oil drops are an integral multiple of excess electrons present on the drops.

We will now find the largest common factor among the numbers representing the charges in zeets.

Since the charges B (4.13x10⁻¹⁴) and C (4.72x10⁻¹⁴) are close enough.

So, the required factor is = 4.72 - 4.13

= 0.59x10^-14

Now,

A 1.77×10⁻¹⁴ / 0.59x10^-14 = 3

B 4.13×10⁻¹⁴ / 0.59x10^-14 = 7

C 4.72×10⁻¹⁴ / 0.59x10^-14 = 8

D 5.31×10⁻¹⁴ / 0.59x10^-14 = 9

E 7.67×10⁻¹⁴ / 0.59x10^-14 = 13

In all the cases the quotients are integers, so it can be assumed that these numbers are the actual number of excess electrons on the drops.

so, the charge on electron is 0.5x10^-14 zeets

= 5.9x10^-14 zeets.