Which data table describes the sun? a. composition mostly frozen nitrogen mass 258.9 × 1018 kg b. composition mostly hydrogen and helium gas mass 1.989 × 1030 kg c. composition fine dust, metals and minerals, and volcanic rock mass 6.4 × 1023 kg d. composition central iron core surrounded by rock, similar to earth mass 4.9 × 1024 kg

The Sun is a star around which our planet Earth and other planets and satellites of our solar system revolve along specific orbits. Sun appears to be spherical in shape and consists of glowing hot gases. It contains mostly hydrogen and helium gases. The temperature of the gas mixture is extremely high.

Therefore, the Sun mostly composed of hydrogen and helium gases.

(Answer) B. Composition mostly hydrogen and helium gas, Mass 1.989 x 10^30 Kg

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:

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.