Millikan's Oil Drop Experiment : Tiny Drops, Big Discoveries

The video explains Robert Milliken's oil drop experiment, which determined the charge of an electron. The setup involved charged plates, an atomizer, and a microscope to observe oil droplets. X-rays ionized the droplets, allowing Milliken to control their movement by adjusting voltage. He calculated the charge on the droplets as multiples of -1.602 x 10^-19 coulombs, identifying the fundamental charge of an electron. Using this charge and J.J. Thompson's charge-to-mass ratio, Milliken calculated the electron's mass as 9.11 x 10^-31 kg, showing it is 1836 times lighter than a hydrogen atom.

What is the primary purpose of the microscope in Milliken's oil drop experiment?

• To measure the voltage across the plates

• To observe the movement of tiny oil droplets

• To charge the oil droplets

• To emit liquid as a fine spray

How are the oil droplets ionized in Milliken's experiment?

• By applying a magnetic field

• By shaking the chamber

• By exposing them to X-rays

• By heating them

What happens to the negatively charged oil droplets when the voltage is increased?

• They move upwards

• They evaporate

• They remain stationary

• They move downwards

What is the relationship between the electric force and gravitational force on the oil droplets at equilibrium?

• Electric force is greater than gravitational force

• Electric force is unrelated to gravitational force

• Electric force is less than gravitational force

• Electric force equals gravitational force

What did Milliken conclude about the charge on an oil droplet?

• It varies with temperature

• It is always positive

• It is an integral multiple of a fundamental charge

• It is a random value

What is the fundamental charge of an electron as determined by Milliken?

• -1.602 x 10^-19 coulombs

• -1.602 x 10^-18 coulombs

• -1.602 x 10^-21 coulombs

• -1.602 x 10^-20 coulombs

Using JJ Thompson's charge-to-mass ratio, what is the calculated mass of an electron?

• 9.11 x 10^-32 kg

• 9.11 x 10^-31 kg

• 9.11 x 10^-30 kg

• 9.11 x 10^-33 kg