Robert Millikan performed experiments that validated Einstein's photoelectric theory and made a very accurate determination of Planck's constant.  These contributions were most helpful to the determination of - 

• the Big Bang theory
• gravitational fields
• the periodic table
• quantum physics

Which of the following is a major difference between electromagnetic force and gravitational field?

• electromagnetic force can attract and repel while the gravitational force can only attract
• electromagnetic force decreases as the distance is increased, gravitational force increases as distance increases
• electromagnetic force relies on a constant while the gravitational force does not 
• all of these are major differences between electromagnetic force and gravity

Take a look at the image.  Which of the following is a free body diagram representing two protons in a nucleus?

• A
• B
• C
• D

Beta decay is the process in which a neutron is changed into a proton, electron, and antineutrino.  Which fundamental force is most responsible for this reaction?

• Electromagnetic
• Gravitational
• Strong Nuclear Force
• Weak Nuclear force

A transformer is a device used to increase or decrease the voltage through induction.  Which fundamental force is responsible for this induction?

• Electromagnetic
• Weak Nuclear
• Strong Nuclear
• Gravitational

What fundamental force is primarily responsible for holding the protons and neutrons together in the nucleus of an atom?

• electromagnetic
• gravitational
• strong nuclear
• weak nuclear

The weak nuclear force is responsible for - 

• pulling two masses together
• the repulsion of like charges
• the radioactive decay of certain atomic nuclei
• holding the nucleus of an atom together

A helium atom is composed of 2 protons, 2 neutrons, and 2 electrons.  In the helium atom, the strong force is the fundamental interaction between the - 

• electrons only
• electrons and protons
• neutrons and protons
• neutrons and electrons

The force that holds the nucleus of an atom together is - 

• weak and short ranged
• strong and short-ranged
• weak and long-ranged
• strong and long-ranged

The strongest of the four fundamental forces is the - 

• electromagnetic
• gravitational
• strong nuclear
• weak nuclear