WGU C165 OA Exam – Integrated Physical
Sciences OA 2023–2024 (400 Questions
with Correct Answers)
Question 1
What is the primary source of energy for Earth’s climate system?
A. Volcanic activity
B. Solar radiation
C. Earth’s core heat
D. Ocean currents
Correct Answer: B. Solar radiation
Rationale : Solar radiation is the primary driver of Earth’s climate system, providing the energy
that fuels atmospheric and oceanic processes, such as weather patterns and temperature
regulation. Volcanic activity, core heat, and ocean currents contribute but are not the primary
source.
Question 2
Which of the following is a characteristic of a controlled experiment?
A. Multiple variables are changed simultaneously
B. Only one variable is manipulated at a time
C. No variables are controlled
D. The experiment is conducted in a natural setting
Correct Answer: B. Only one variable is manipulated at a time
Rationale : A controlled experiment isolates the effect of one independent variable on the
dependent variable by keeping all other variables constant, ensuring reliable results.
,Question 3
What is the definition of density?
A. Mass multiplied by volume
B. Mass divided by volume
C. Volume divided by mass
D. Weight multiplied by volume
Correct Answer: B. Mass divided by volume
Rationale : Density is defined as mass per unit volume (ρ = m/V). It measures how much matter
is packed into a given space.
Question 4
Which layer of Earth’s atmosphere contains the ozone layer?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
Correct Answer: B. Stratosphere
Rationale : The ozone layer, which absorbs harmful ultraviolet radiation, is located in the
stratosphere, approximately 10–50 km above Earth’s surface.
Question 5
What type of change occurs when water evaporates from a sidewalk?
A. Chemical change
B. Physical change
C. Nuclear change
D. Thermal change
Correct Answer: B. Physical change
Rationale : Evaporation is a physical change because water changes from liquid to gas without
altering its chemical composition (H₂O).
Question 6
,Which of Newton’s laws states that an object at rest stays at rest unless acted upon by an
external force?
A. First Law
B. Second Law
C. Third Law
D. Law of Gravitation
Correct Answer: A. First Law
Rationale : Newton’s First Law (Law of Inertia) states that an object remains in its state of rest or
uniform motion unless an external force acts on it.
Question 7
What type of chemical bond holds two atoms together in a molecule?
A. Ionic bond
B. Covalent bond
C. Metallic bond
D. Hydrogen bond
Correct Answer: B. Covalent bond
Rationale : A covalent bond involves the sharing of electrons between two atoms to form a
molecule, such as in H₂O or O₂.
Question 9
What is the primary source of energy for Earth’s tectonic plate movement?
A. Solar energy
B. Geothermal energy
C. Tidal forces
D. Magnetic fields
Correct Answer: B. Geothermal energy
Rationale : Geothermal energy from Earth’s core drives convection currents in the mantle,
causing tectonic plate movement.
Question 10
, Which of the following is a mechanical wave?
A. Light wave
B. Radio wave
C. Sound wave
D. X-ray
Correct Answer: C. Sound wave
Rationale : Mechanical waves, like sound waves, require a medium (e.g., air, water) to travel,
unlike electromagnetic waves (light, radio, X-rays).
Question 11
What is the primary composition of Earth’s atmosphere?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Argon
Correct Answer: B. Nitrogen
Rationale : Nitrogen makes up approximately 78% of Earth’s atmosphere, with oxygen at about
21%.
Question 12
How is a compound formed?
A. Electrons are transferred between atoms
B. Atoms are physically mixed
C. Molecules are broken apart
D. Elements are heated together
Correct Answer: A. Electrons are transferred between atoms
Rationale : Compounds form through chemical bonds (ionic or covalent), involving electron
transfer or sharing between atoms.
Question 13
What is the unit of force in the SI system?
Sciences OA 2023–2024 (400 Questions
with Correct Answers)
Question 1
What is the primary source of energy for Earth’s climate system?
A. Volcanic activity
B. Solar radiation
C. Earth’s core heat
D. Ocean currents
Correct Answer: B. Solar radiation
Rationale : Solar radiation is the primary driver of Earth’s climate system, providing the energy
that fuels atmospheric and oceanic processes, such as weather patterns and temperature
regulation. Volcanic activity, core heat, and ocean currents contribute but are not the primary
source.
Question 2
Which of the following is a characteristic of a controlled experiment?
A. Multiple variables are changed simultaneously
B. Only one variable is manipulated at a time
C. No variables are controlled
D. The experiment is conducted in a natural setting
Correct Answer: B. Only one variable is manipulated at a time
Rationale : A controlled experiment isolates the effect of one independent variable on the
dependent variable by keeping all other variables constant, ensuring reliable results.
,Question 3
What is the definition of density?
A. Mass multiplied by volume
B. Mass divided by volume
C. Volume divided by mass
D. Weight multiplied by volume
Correct Answer: B. Mass divided by volume
Rationale : Density is defined as mass per unit volume (ρ = m/V). It measures how much matter
is packed into a given space.
Question 4
Which layer of Earth’s atmosphere contains the ozone layer?
A. Troposphere
B. Stratosphere
C. Mesosphere
D. Thermosphere
Correct Answer: B. Stratosphere
Rationale : The ozone layer, which absorbs harmful ultraviolet radiation, is located in the
stratosphere, approximately 10–50 km above Earth’s surface.
Question 5
What type of change occurs when water evaporates from a sidewalk?
A. Chemical change
B. Physical change
C. Nuclear change
D. Thermal change
Correct Answer: B. Physical change
Rationale : Evaporation is a physical change because water changes from liquid to gas without
altering its chemical composition (H₂O).
Question 6
,Which of Newton’s laws states that an object at rest stays at rest unless acted upon by an
external force?
A. First Law
B. Second Law
C. Third Law
D. Law of Gravitation
Correct Answer: A. First Law
Rationale : Newton’s First Law (Law of Inertia) states that an object remains in its state of rest or
uniform motion unless an external force acts on it.
Question 7
What type of chemical bond holds two atoms together in a molecule?
A. Ionic bond
B. Covalent bond
C. Metallic bond
D. Hydrogen bond
Correct Answer: B. Covalent bond
Rationale : A covalent bond involves the sharing of electrons between two atoms to form a
molecule, such as in H₂O or O₂.
Question 9
What is the primary source of energy for Earth’s tectonic plate movement?
A. Solar energy
B. Geothermal energy
C. Tidal forces
D. Magnetic fields
Correct Answer: B. Geothermal energy
Rationale : Geothermal energy from Earth’s core drives convection currents in the mantle,
causing tectonic plate movement.
Question 10
, Which of the following is a mechanical wave?
A. Light wave
B. Radio wave
C. Sound wave
D. X-ray
Correct Answer: C. Sound wave
Rationale : Mechanical waves, like sound waves, require a medium (e.g., air, water) to travel,
unlike electromagnetic waves (light, radio, X-rays).
Question 11
What is the primary composition of Earth’s atmosphere?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Argon
Correct Answer: B. Nitrogen
Rationale : Nitrogen makes up approximately 78% of Earth’s atmosphere, with oxygen at about
21%.
Question 12
How is a compound formed?
A. Electrons are transferred between atoms
B. Atoms are physically mixed
C. Molecules are broken apart
D. Elements are heated together
Correct Answer: A. Electrons are transferred between atoms
Rationale : Compounds form through chemical bonds (ionic or covalent), involving electron
transfer or sharing between atoms.
Question 13
What is the unit of force in the SI system?
