Question

question 7 of 10
what did robert millikan discover?

a. he determined an electrons charge.

b. he discovered the nucleus of the atom.

c. he discovered that electrons orbited inside an atom.

d. he determined the radius of oil drops.

Explanation:

Robert Millikan is known for the oil - drop experiment, through which he determined the charge of an electron. Option B: The nucleus of the atom was discovered by Ernest Rutherford. Option C: The idea that electrons orbit the nucleus (in specific energy levels) was proposed by Niels Bohr, and the general concept of electron orbits within the atom was part of the Bohr model and later quantum mechanical models, not Millikan's work. Option D: Millikan's oil - drop experiment was not about determining the radius of oil drops; it was about using the oil drops to find the electron's charge.

Answer:

A. He determined an electron's charge.