The atomic theory has been revised over time .. j. j thompson described the atom as having a mix of positive and negative charges randomly scattered throughout a sphere of space ruthford's experiments proved this model incorrect and developed the model with a tiny positively charged nucleus .. today, the model is more complex posting a cloud of electrons around a nucleus of protons and neutrons. why has the atomic theory changed during the last several hundred years.
a the splitting of the first atom created the need for a new model
b modern scientific methods are more reliable in developing theories
c the atom has changed over time and the model reflects those changes
d as new discoveries are made existing theories are revising or replaced

not too sure thinking it will always be directed towards the centre of the earth. could be wrong not sure

nec chapter 5 contains

c. information on special occupancy areas

nec chapter 6 covers

a. special equipment

which of the following rules contain the words shall or shall not and must be adhered to?

b. mandatory rules

which of the following rules identify actions that are allowed but not required and typically cover options or alternative methods?

c. optional rules

which of the following serves as the introduction to the nec and provides an overview of the book?

a. nec article 90

organizations that test products for safety are

c. nrtls

the nec is published by the

a national fire protection association

the nec is divided into

b. 9 chapters

the nec provides informative annexes for

c. informational materials and examples

two terms from nec article 100 that trainees should become familiar with are

b. labeled and listed

explanation: