1. Which of the following statements regarding the temperature inside the Earth is correct?
a) Temperature decreases with depth
b) Temperature remains constant below the crust
c) Temperature increases uniformly at all depths
d) Temperature increases with depth at an average rate of about 1°C per 33 meters
Answer: d)
The geothermal gradient indicates that the temperature increases by approximately 1°C every 33 meters in the upper crust, although this rate decreases with greater depths.
2. The Earth's inner core is believed to be:
a) Completely molten
b) In a semi-solid state
c) Gaseous due to high temperature
d) Solid due to immense pressure
Answer: d)
Despite extremely high temperatures, the inner core remains solid due to the immense pressure at that depth.
3. Which of the following layers of the Earth has a partially molten region known as the asthenosphere?
a) Crust
b) Upper mantle
c) Lower mantle
d) Outer core
Answer: b)
The asthenosphere, located within the upper mantle, is partially molten, allowing tectonic plates to move over it.
4. Which one of the following best describes the pressure conditions inside the Earth?
a) Pressure decreases with increasing depth
b) Pressure remains constant throughout the mantle
c) Pressure increases with increasing depth
d) Pressure is highest in the crust
Answer: c)
Due to the weight of overlying rocks, pressure increases significantly as we go deeper inside the Earth.
5. The Mohorovičić discontinuity (Moho) separates:
a) Inner core and outer core
b) Mantle and core
c) Crust and mantle
d) Lithosphere and asthenosphere
Answer: c)
The Moho is the boundary between the Earth’s crust and mantle, where a marked change in seismic wave velocity is observed.
6. At approximately what depth is the outer core of the Earth located?
a) 10–30 km
b) 30–100 km
c)100–2900 km
d) 2900–5100 km
Answer: d)
The outer core begins at about 2900 km depth and extends to around 5100 km. It is in a liquid state.
7. Which of the following correctly represents the state of matter in the Earth's layers from crust to inner core?
a) Solid → Liquid → Solid → Gas
b) Solid → Solid → Liquid → Solid
c) Solid → Plastic → Liquid → Solid
d) Solid → Liquid → Liquid → Gas
Answer: c)
Crust: Solid
Mantle: Solid but behaves plastically in asthenosphere
Outer core: Liquid
Inner core: Solid
8. Which property increases the most rapidly with depth inside the Earth?
a) Density
b) Temperature
c) Pressure
d) All increase equally
Answer: c)
Although all increase, pressure increases most rapidly due to the weight of overlying materials.
9. The temperature at the boundary between the mantle and the outer core (core-mantle boundary) is estimated to be around:
a) 500°C
b) 1500°C
c) 3000°C
d). 4000–5000°C
Answer: d)
The core-mantle boundary temperature is extremely high, estimated to be between 4000°C and 5000°C.
10. What causes the Earth's inner core to remain solid despite temperatures exceeding 5000°C?
a) Low density of materials
b) Presence of magnetic field
c) High radioactive activity
d) Immense pressure at the center
Answer: d)
The enormous pressure at the Earth’s center prevents the inner core from melting, keeping it solid despite extreme temperatures.
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