1. Which atmospheric layer contains Ions and helps in wireless communication?
A. Mesosphere
B. Thermosphere
C. Troposphere
D. Stratosphere
Solution
The correct answer is Thermosphere.
Key Points
The atmosphere consists of different layers with varying densities and temperatures. The column of the atmosphere is divided into five different layers depending upon the temperature condition.
They are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
- The troposphere
- It is the lowest part of the Earth’s atmosphere in which all tropical changes take place. It contains about 75% of the total air in the atmosphere.
- This layer contains dust particles and water vapor.
- All changes in climate and weather take place in this layer.
- This is the most important layer for all biological activity.
- The zone separating the troposphere from the stratosphere is known as the tropopause.
- The temperature here is nearly constant, and hence, it is called tropopause.
- The stratosphere
- It is found above the tropopause and extends up to a height of 50 km.
- One important feature of the stratosphere is that it contains the ozone layer.
- This layer absorbs ultraviolet radiation and shields life on the earth from an intense, harmful form of energy.
- The stratopause caps the top of the stratosphere.
- The mesosphere
- It lies above the stratosphere, which extends up to a height of 80 km.
- In this layer, once again, the temperature starts decreasing with the increase in altitude and reaches up to minus 100°C at a height of 80 km.
- The upper limit of the mesosphere is known as mesopause.
- The thermosphere
- It is located between 80 and 400 km above the mesopause.
- It contains electrically charged particles known as ions, and hence, it is also known as the ionosphere.
- Radio waves transmitted from the earth are reflected back to the earth by this layer.
- It contains Ions and helps in wireless communication
- The temperature here starts increasing with height.
- The exosphere
- It is the uppermost layer of the atmosphere.
- This is the highest layer but very little is known about it.
- Whatever contents are there, these are extremely rarefied in this layer, and it gradually merges with outer space.
2. The _________ is responsible for Earth’s magnetic field.
A. Mantle
B. Crust
C. Outer core
D. Inner core
Solution
The correct answer is outer core.
Important Points
- The interior of the earth is divided into three parts namely Crust, Mantle, and Core.
- The core is the innermost layer of the earth.
- The radius of the innermost layer(core) is about 3500 km.
- The core is made up of material constituted by nickel and iron.
- The temperature and pressure of the central core are very high.
Key Points
- The core is further subdivided into two layers called the outer core and inner core.
- The outer core of the earth is in a liquid state.
- The inner core is in solid-state
- The outer core is responsible for the earth’s magnetic field.
Additional Information
- The crust is the outermost of the earth.
- It is brittle in nature.
- it the thinnest layer of Earth.
- The thickness of the crust varies under the oceanic and continental areas.
- The mantle is the second layer in the interior of the earth.
- The mantle extends from Moho’s discontinuity to a depth of 2,900 km.
- The upper portion of the mantle is called the asthenosphere.
3. Which among the following is NOT a Jovian planet?
A. Mercury
B. Neptune
C. Jupiter
D. Saturn
Solution
The correct answer is Mercury.
Key Points
- The first four planets are called Terrestrial, meaning earth-like planets like Mercury, Venus, Earth, and Mars.
- They are also called inner planets.
- They lie between the sun and the belt of asteroids.
- They are made up of rock and metals and have relatively high densities.
- The terrestrial planets were formed in the close vicinity of the parent star where it was too warm for gases to condense to solid particles.
- The terrestrial planets are smaller and their lower gravity could not hold the escaping gases.
- Other than them the planets are called jovian or giant planets likeJupiter, Saturn, Uranus, and Neptune.
- They are also called the outer planets.
- Most of them are much larger than the terrestrial planets and have a thick atmosphere, mostly of helium and hydrogen.
- The solar winds were not all that intense to cause the removal of gases from the Jovian planets.
Additional Information
Inner or Terrestrial planets:
- Mercury
- Venus
- Earth
- Mars
Outer Planets or Jovian planets:
- Jupiter
- Saturn
- Uranus
- Neptune
Shortcut Trick
- My Very Excited Mother Just Served Us Nachos
- M → Mercury, V → Venus, E → Earth, M → Mars, J → Jupiter, S → Saturn, U → Uranus, N → Neptune
4. Which of the following is the longest strait in the world?
A. Malacca Strait
B. Sunda Strait
C. Denmark Strait
D. Bering Strait
Solution
The correct answer is Malacca Strait.
Key Points
- Malacca Strait
- The Strait of Malacca connects the Andaman Sea (Indian Ocean) and the South China Sea (Pacific Ocean).
- Stretching about 800km, it is the longest straits in the world and facilitates not just shipping and the movement of people in the surrounding communities but is a confluence of trade, cultures, ideas, and knowledge between the East and West.
- It runs between the Indonesian island of Sumatra to the west and peninsular (West) Malaysia and extreme southern Thailand to the east and has an area of about 25,000 square miles (65,000 square km).
- Singapore, one of the world’s most important ports, is situated at the strait’s southern end.
- The global shift in economic power from the West to the East coupled with burgeoning trade, investments, and production in areas spanning the Indian and Pacific Ocean regions has given increasing importance to this region.
5. Laterite soil is rich in:
A. Phosphorus
B. Calcium carbonate
C. Potassium
D. Iron oxide
Solution
The correct answer is Iron Oxide.
Key Points
- Laterite is a Latin word that means “Later”.
- Francis Hamilton (a Scottish Physician) first described and named a laterite formation in Southern India in 1807.
- Laterite is both soil and a rock type and rich in Iron & Aluminium.
- Nearly all laterites are of rusty-red coloration, because of high iron oxide content.
- They evolve by intense and sustained weathering of the underlying parent rock.
- Laterite soils have a high content of clay, which ensures that they have a greater ability to exchange cations and retain water than sandy soils, and can thus be used as a hard material like a brick.
- It is formed in hot & wet tropical areas & majorly found between the Tropics of Cancer and Capricorn.
- Angkor wat in Cambodia is an example for use of laterite soil as a construction material.
Example of construction with Laterite in Angkor, Cambodia
6. Which of the following options has the correct sequence of mountain ranges from North to South in India?
A. Zaskar, Karakoram, Ladakh, Shiwalik
B. Ladakh, Karakoram, Shiwalik, Zaskar
C. Karakoram, Zaskar, Ladakh, Shiwalik
D. Karakoram, Ladakh, Zaskar, Shiwalik
Solution
The correct answer is Karakoram, Ladakh, Zaskar, Shiwalik.
Key Points
| Mountain Range | Important facts |
| Karakoram Range | K2, the second-highest peak in the world is located in this range.Famous Glaciers: Siachen Glacier, Biafo Glacier.Located in the regions of Gilgit – Baltistan, Ladakh, and Xinjiang region |
| Ladakh Range | India’s cold desert ‘LEH’ is situated here.The extension of the Ladakh Range into China is known as Kailash Range. |
| Zaskar Range | Lies here Coldest place in India, Dras (The Gateway to Ladakh)Famous Passes : Shipki, Lipu Lekh (Lipulieke), and Mana Pass.Highest peak Kamet. |
| Shivalik Range | Also known as Outer Himalayas.Located in between the Great Plains and Lesser Himalayas.Runs for a distance of 2,400 km from the Potwar Plateau to the Brahmaputra valley. |
7. Which meridian or longitude is also termed as the Standard Meridian of India?
A. 27°30’E
B. 27°30’W
C. 82°30’W
D. 82°30’E
Solution
The correct answer is 82°30’E.
- 82°30’E meridian or longitude is also termed as the Standard Meridian of India.
- The standard meridian of India is east of the Greenwich Meridian.
- Indian Standard time has a time offset of UTC+05:30.
- Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich.
Important Points
Standard Meridian of India passes through:
- Uttar Pradesh
- Madhya Pradesh
- Chhattisgarh
- Orissa
- Andhra Pradesh
8. The most abundant metal in the earth crust is
A. Sodium
B. Aluminium
C. Calcium
D. Iron
Solution
Option 2 is correct, i.e. Aluminium.
Key Points
- Aluminium is the most plentiful (most abundant) of metals in the crust of the earth.
- Aluminium is around 8.1 per cent of the total metals on the surface of the earth.
Important Points
- The most plentiful non-metal in the earth’s surface is Oxygen.
- The most plentiful metalloid in the crust of the earth is Silicon.
- O > Si > Al > Fe > Ca are the most abundant elements in the earth crust.
9. Which one of the following countries is NOT located on the Tropic of Capricorn?
A. Chile
B. Brazil
C. Paraguay
D. Uruguay
Solution
The correct answer is Uruguay.
Key Points
- Total ten countries are located on the Tropic of Capricorn. They are spread over three continents. Out of the ten countries located on the Tropic of Capricorn, five are African countries.
- They are Namibia, Botswana, South Africa, Mozambique, and Madagascar. Argentina, Brazil, Chile, and Paraguay are South American countries located on the Tropic of Capricorn.
- In addition to five African countries and four South American countries, Australia is also located on the Tropic of Capricorn. Hence option 4 is correct.
Important Points
- EQUATOR/ TROPIC OF CANCER/ TROPIC OF CAPRICORN PASSES THROUGH COUNTRIES
- Tropic of Capricorn( 23.5 degrees south latitude):
- South America:
- Chile, Argentina, Paraguay, and Brazil.
- Africa:
- Nambia, Botswana, South Africa, Mozambique, and Madagascar.
- Australia
- French Polynesia
Additional Information
- Equator Line( 0 degree latitude)
- In South America
- Ecuador, Colombia, and Brazil.
- Africa
- Sao tome and Principle, Gabon, Republic of Congo, The Democratic Republic of Cango, Uganda, Kenya, and Somalia.
- Asia
- Maldives, Indonesia, and Kiribati.
- Tropic of Cancer( 23.5 degrees North Latitude)
- North America
- Mexico, and the Bahamas.
- Africa:
- Mauritania, Western Sahara, Mali, Algeria, Niger, Libya, and Egypt.
- Asia:
- Saudi Arabia, UAE, Oman, India, Bangladesh, Myanmar, China, and Taiwan.
10. Which among the following countries is the largest producer of Bauxite in the world?
A. Australia
B. Brazil
C. China
D. India
Solution
The correct answer is Australia.
Important Points
- Bauxite:
- It is an ore of aluminium.
- It is a light and versatile material, having wide industrial uses such as in aeroplane industry, machine tools, electricals and utensil industry.
- It is mostly mined in tropical regions but aluminium is manufactured in developed countries where cheap electricity is abundantly available.
- Australia is the largest producer of Bauxite in the world, accounts for 32% (approx) of the world’s production and also has about 40% of Bauxite reserves.
- Australia produces nearly 100 million metric tons in the year 2019.
- Guinea is the second-largest producer of Bauxite in the world for the year 2019 with a production of nearly 80 million metric tons, while China is the third followed by Brazil and India with fourth and fifth positions respectively.
