AFCT General Science: Physical and Chemical 3

Question 1

What is the difference between speed and velocity?

Accepted Answer

Speed is a scalar quantity (magnitude only); velocity is a vector quantity (magnitude and direction)

Answer

Speed is a scalar quantity that describes how fast an object is moving (magnitude only). Velocity is a vector quantity that describes both how fast and in what direction an object is moving. An object moving in a circle at constant speed has changing velocity.

Question 2

What happens during an exothermic chemical reaction?

Accepted Answer

Energy is released to the surroundings, usually as heat

Answer

In an exothermic reaction, the products have less chemical energy than the reactants, and the difference is released to the surroundings as heat (and sometimes light or sound). Combustion is a common example.

Question 3

What is the relationship between wavelength and frequency of electromagnetic waves?

Accepted Answer

They are inversely proportional; as wavelength increases, frequency decreases

Answer

Wavelength and frequency are inversely proportional for electromagnetic waves. Since all electromagnetic waves travel at the speed of light (c), the equation c = λf shows that as wavelength (λ) increases, frequency (f) must decrease, and vice versa.

Question 4

What are the three states of matter and what distinguishes them?

Accepted Answer

Solid, liquid, gas — distinguished by particle arrangement, motion, and energy

Answer

The three common states of matter are solid (fixed shape and volume, closely packed particles), liquid (fixed volume but variable shape, particles slide past each other), and gas (variable shape and volume, widely spaced particles moving freely).

Question 5

What is an isotope?

Accepted Answer

An atom with the same number of protons but a different number of neutrons

Answer

Isotopes are atoms of the same element that have the same number of protons (same atomic number) but different numbers of neutrons (different mass numbers). For example, Carbon-12 and Carbon-14 are both carbon but have 6 and 8 neutrons respectively.

(AFCT) Armed Forces Classification Test Practice Test

(AFCT) Armed Forces Classification Test Practice Test

AFCT General Science: Physical and Chemical 3