Static Quiz 23 March 2026 (Geography)

Q1.Consider the following pairs (Seismic Discontinuity – Boundary it demarcates):

1. Mohorovicic discontinuity – Boundary between crust and mantle
2. Gutenberg discontinuity – Boundary between mantle and liquid outer core
3. Lehmann discontinuity – Boundary between outer core and inner core

Which of the above pairs are correctly matched?
A. 1 and 2 only
B. 2 and 3 only
C. 1, 2 and 3
D. 1 only

Q1. (C)

Explanation:

• 1 correct → Moho marks sharp increase in seismic velocity due to transition from lighter crust to denser mantle.
• 2 correct → Gutenberg indicates disappearance of S-waves → confirms liquid outer core.
• 3 correct → Lehmann marks transition to solid inner core (based on P-wave behaviour).

Q2.  

Assertion (A): The inner core of the Earth remains solid despite temperatures exceeding the melting point of iron.
Reason (R): The immense pressure at the Earth’s center raises the melting point of materials.

A. Both A and R are correct and R is the correct explanation of A
B. Both A and R are correct but R is not the correct explanation
C. A is correct but R is incorrect
D. A is incorrect but R is correct

Q2. (A)

Explanation:

• Assertion correct → inner core is solid (~5000–6000°C).
• Reason correct → pressure (~3–4 million times atmospheric) increases melting point.
• Causal link → high pressure offsets temperature → solid state maintained.

Q3.  

Assertion (A): Oceanic crust is denser than continental crust.
Reason (R): Oceanic crust is primarily composed of silica and aluminium (SiAl).

A. Both A and R are correct and R explains A
B. Both A and R are correct but R does not explain A
C. A is correct but R is incorrect
D. A is incorrect but R is correct

Q3. (C)

Explanation:

• Assertion correct → Oceanic crust density ≈ 2.9 g/cm³ > Continental ≈ 2.7 g/cm³.
• Reason incorrect → Oceanic crust is SiMa (Silica + Magnesium), not SiAl.

Q4. Match the following geological terms with their correct associations:

List I	List II
A. SiAl	1. Oceanic crust
B. SiMa	2. Continental crust
C. NiFe	3. Earth’s core
D. Low Velocity Zone (LVZ)	4. Asthenosphere

Select the correct code:
A. A-2, B-1, C-3, D-4
B. A-1, B-2, C-3, D-4
C. A-2, B-1, C-4, D-3
D. A-1, B-2, C-4, D-3

Q4. (A)

Explanation:

• A-2 → SiAl = continental crust (lighter, felsic).
• B-1 → SiMa = oceanic crust (denser, mafic).
• C-3 → NiFe = core composition (iron + nickel).
• D-4 → LVZ = asthenosphere (semi-molten, reduced velocity).

Q5.Consider the following statements regarding the physical conditions inside the Earth:

1. The geothermal gradient remains uniform throughout the Earth’s interior.
2. Density of Earth’s materials increases with depth.
3. Pressure at the Earth’s center is estimated to be about 3–4 million times atmospheric pressure.

How many of the above statements are correct?
A. Only one
B. Only two
C. All three
D. None

Q5. (B)

Explanation:

• 1 incorrect → geothermal gradient is non-linear (high near crust, varies in mantle/core).
• 2 correct → heavier elements concentrated inward due to differentiation.
• 3 correct → extreme pressure at core (~3–4 million atm).

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