# By definition, the electric displacement current through a surface S is proportional to the

1. magnitude flux through S
2. rate of change of the magnetic flux through S
3. time integral of the magnetic flux through S
4. the electric flux through S
5. rate of change of the electric flux through S

# Who discovered a spin quantum number?

1. Unlenbeck and Goudsmit
2. Nell’s Bohr
3. Zeeman
4. Sommerfield

# In Bohr’s hydrogen atomic model, the radius of the stationary

orbit is directly proportional to (n = principal quantum number)

1. n2
2. n-2
3. 2n2
4. 3n3

# The first successful theory of atomic structure was introduced by

1. Neil Bohr
2. Einstein
3. J.J. Thomson
4. Rutherford