ESTUDYR
NJIT PHYSICS 203 FINAL PRACTICE 2025 MULTICHOICE ANSWERED
EXAM QUESTIONS WITH DETAILED RATIONALES
Why does Earth have a magnetic field?
A. Due to the proximity of the Sun
B. Due to the Earth's liquid outer core
C. Due to content of atmospheric gases
D. Due to the types of rocks found in the lithosphere
Answer: B.
Rationale: Convective motion of conducting molten iron in the outer core + Earth's rotation
generates a geodynamo that produces the magnetic field.
Which statement about disturbance waves from an earthquake is true?
A. Most damage is caused by surface waves
B. Most damage is caused by P-waves
C. Most damage is caused by S-waves
Answer: A.
Rationale: Surface waves (Love and Rayleigh) typically have largest amplitudes and cause
greatest ground shaking and damage.
Which earthquake wave has the highest propagation speed?
A. Surface waves
B. P-waves (primary/compressional)
C. S-waves (shear)
Answer: B.
Rationale: P-waves are compressional body waves and travel faster than S-waves and surface
waves.
Why do Earth’s seasons occur?
A. The Sun increases and decreases output based on the orbit
B. Insolation varies annually because of Earth's axial tilt
C. Earth gets closer and farther from the Sun during orbit
Answer: B.
Rationale: Axial tilt (~23.5°) changes solar angle and day length through the year; distance
variation is minor.
Where is seafloor returned to the mantle?
A. Trenches
B. Mid-ocean ridges
,ESTUDYR
C. Along coastlines
Answer: A.
Rationale: Subduction zones (ocean trenches) are where oceanic lithosphere sinks back into the
mantle.
What happens to the age of seafloor rocks as they move away from a mid-ocean ridge?
A. The rocks get younger
B. The rock ages do not change
C. The rocks get older
Answer: C.
Rationale: New crust forms at ridges; moving away, crust becomes progressively older.
When an oceanic plate collides with a continental plate, what happens?
A. The continental plate is subducted
B. The oldest plate is subducted
C. The oceanic plate is subducted
Answer: C.
Rationale: Oceanic lithosphere is denser and thinner, so it sinks beneath continental
lithosphere.
Which volcano type is most likely to have violent eruptions and why?
A. Stratovolcano — magma is more viscous than in shield volcanoes
B. Stratovolcano — magma is less viscous than shield volcanoes
C. Shield — magma is less viscous than stratovolcanoes
D. Shield — magma is more viscous than stratovolcanoes
Answer: A.
Rationale: High-viscosity (silica-rich) magma traps volatiles, promoting explosive eruptions
typical of stratovolcanoes.
Radioactive half-life Q: A isotope has t½ = 500 Myr. Sample has 3× as many daughters as
parents. Age = ?
A. 500 million years
B. 1,000 million years
C. 1,500 million years
D. 2,500 million years
Answer: C.
Rationale: Daughters:parents = 3:1 ⇒ after n half-lives, daughter/parent = (2^n − 1). Solve 2^n
− 1 = 3 → 2^n = 4 → n = 2 half-lives → age = 2 × 500 = 1000? Wait — check: actually initial
parent P0, after n half-lives parent = P0/2^n, daughter = P0 − P0/2^n = P0(1 − 1/2^n). Ratio
daughter/parent = (2^n − 1). If daughter/parent = 3, then 2^n −1 = 3 ⇒ 2^n =4 ⇒ n=2 ⇒ age =
, ESTUDYR
2×500 = 1000 Myr. Correct answer should be 1,000 Myr.
Correction & Final: B. 1,000 million years.
Corrected rationale: Daughter:parent = 3:1 implies two half-lives have passed (2^2 = 4), so age
= 2 × 500 = 1,000 Myr.
What causes the large-scale circular ocean surface current patterns (gyres)?
A. Winds
B. Ocean thermal effects
C. Ocean salinity effects
D. Ocean thermal and salinity effects
Answer: A.
Rationale: Persistent wind patterns (trade winds, westerlies) drive surface currents; Coriolis
effect shapes gyres.
If the Moon were farther from Earth, what happens to spring tides?
A. Tides would be higher
B. Tides would be lower
C. No change to spring tides
Answer: B.
Rationale: Gravitational force decreases with distance², so tidal amplitude would reduce.
At which margin would waves begin breaking farthest from the beach?
A. Active margin
B. Passive margin
Answer: B.
Rationale: Passive margins have broad, gently sloping continental shelves → waves shoal and
can break farther offshore.
Standing on a beach, a ball sits 15 m offshore and waves are about to reach it but only break
nearer the beach. Where will the ball be when the last wave reaches the beach?
A. Closer to shore
B. About the same position
C. Farther offshore
Answer: B.
Rationale: In deep water or non-breaking region, orbital motion moves water but net transport
(longshore/drift) may be small; if waves haven't broken, little net shoreward movement of
floating object.
If large glacier melt adds freshwater to the North Atlantic, the global ocean conveyor belt will
likely:
NJIT PHYSICS 203 FINAL PRACTICE 2025 MULTICHOICE ANSWERED
EXAM QUESTIONS WITH DETAILED RATIONALES
Why does Earth have a magnetic field?
A. Due to the proximity of the Sun
B. Due to the Earth's liquid outer core
C. Due to content of atmospheric gases
D. Due to the types of rocks found in the lithosphere
Answer: B.
Rationale: Convective motion of conducting molten iron in the outer core + Earth's rotation
generates a geodynamo that produces the magnetic field.
Which statement about disturbance waves from an earthquake is true?
A. Most damage is caused by surface waves
B. Most damage is caused by P-waves
C. Most damage is caused by S-waves
Answer: A.
Rationale: Surface waves (Love and Rayleigh) typically have largest amplitudes and cause
greatest ground shaking and damage.
Which earthquake wave has the highest propagation speed?
A. Surface waves
B. P-waves (primary/compressional)
C. S-waves (shear)
Answer: B.
Rationale: P-waves are compressional body waves and travel faster than S-waves and surface
waves.
Why do Earth’s seasons occur?
A. The Sun increases and decreases output based on the orbit
B. Insolation varies annually because of Earth's axial tilt
C. Earth gets closer and farther from the Sun during orbit
Answer: B.
Rationale: Axial tilt (~23.5°) changes solar angle and day length through the year; distance
variation is minor.
Where is seafloor returned to the mantle?
A. Trenches
B. Mid-ocean ridges
,ESTUDYR
C. Along coastlines
Answer: A.
Rationale: Subduction zones (ocean trenches) are where oceanic lithosphere sinks back into the
mantle.
What happens to the age of seafloor rocks as they move away from a mid-ocean ridge?
A. The rocks get younger
B. The rock ages do not change
C. The rocks get older
Answer: C.
Rationale: New crust forms at ridges; moving away, crust becomes progressively older.
When an oceanic plate collides with a continental plate, what happens?
A. The continental plate is subducted
B. The oldest plate is subducted
C. The oceanic plate is subducted
Answer: C.
Rationale: Oceanic lithosphere is denser and thinner, so it sinks beneath continental
lithosphere.
Which volcano type is most likely to have violent eruptions and why?
A. Stratovolcano — magma is more viscous than in shield volcanoes
B. Stratovolcano — magma is less viscous than shield volcanoes
C. Shield — magma is less viscous than stratovolcanoes
D. Shield — magma is more viscous than stratovolcanoes
Answer: A.
Rationale: High-viscosity (silica-rich) magma traps volatiles, promoting explosive eruptions
typical of stratovolcanoes.
Radioactive half-life Q: A isotope has t½ = 500 Myr. Sample has 3× as many daughters as
parents. Age = ?
A. 500 million years
B. 1,000 million years
C. 1,500 million years
D. 2,500 million years
Answer: C.
Rationale: Daughters:parents = 3:1 ⇒ after n half-lives, daughter/parent = (2^n − 1). Solve 2^n
− 1 = 3 → 2^n = 4 → n = 2 half-lives → age = 2 × 500 = 1000? Wait — check: actually initial
parent P0, after n half-lives parent = P0/2^n, daughter = P0 − P0/2^n = P0(1 − 1/2^n). Ratio
daughter/parent = (2^n − 1). If daughter/parent = 3, then 2^n −1 = 3 ⇒ 2^n =4 ⇒ n=2 ⇒ age =
, ESTUDYR
2×500 = 1000 Myr. Correct answer should be 1,000 Myr.
Correction & Final: B. 1,000 million years.
Corrected rationale: Daughter:parent = 3:1 implies two half-lives have passed (2^2 = 4), so age
= 2 × 500 = 1,000 Myr.
What causes the large-scale circular ocean surface current patterns (gyres)?
A. Winds
B. Ocean thermal effects
C. Ocean salinity effects
D. Ocean thermal and salinity effects
Answer: A.
Rationale: Persistent wind patterns (trade winds, westerlies) drive surface currents; Coriolis
effect shapes gyres.
If the Moon were farther from Earth, what happens to spring tides?
A. Tides would be higher
B. Tides would be lower
C. No change to spring tides
Answer: B.
Rationale: Gravitational force decreases with distance², so tidal amplitude would reduce.
At which margin would waves begin breaking farthest from the beach?
A. Active margin
B. Passive margin
Answer: B.
Rationale: Passive margins have broad, gently sloping continental shelves → waves shoal and
can break farther offshore.
Standing on a beach, a ball sits 15 m offshore and waves are about to reach it but only break
nearer the beach. Where will the ball be when the last wave reaches the beach?
A. Closer to shore
B. About the same position
C. Farther offshore
Answer: B.
Rationale: In deep water or non-breaking region, orbital motion moves water but net transport
(longshore/drift) may be small; if waves haven't broken, little net shoreward movement of
floating object.
If large glacier melt adds freshwater to the North Atlantic, the global ocean conveyor belt will
likely:
