Prelims - Smart Questions Solving Technique - USE OF GENERAL KNOWLEDGE OR COMMON SENSE

The Use of General Knowledge or Common-Sense method is particularly useful when you're faced with a question in the UPSC CSE Prelims for which you don't have direct subject knowledge. UPSC often includes questions that can be answered logically, even without deep knowledge of the topic, by using everyday understanding of how things work, basic reasoning, and broad general knowledge about the world.

In these situations, you can apply your common sense and general understanding to rule out improbable answers and select the most logical option.

1.        Step 1: Identify Broad or Familiar Topics

o    Look for options related to everyday events, well-known facts, or general principles. Even if you don’t know the specifics, broad familiarity with the world or logic can guide you.

2.        Step 2: Focus on What Seems Logically Likely

o    If something sounds too extreme or unreasonable, it's often incorrect. Choose the option that seems the most balanced and logical.

3.        Step 3: Avoid Overcomplicating

o    Sometimes, the simplest explanation or answer is the correct one. Don’t overthink the question if a common-sense approach fits the scenario.

4.        Step 4: Eliminate Improbable Options

o    Narrow down the options by eliminating those that seem factually unlikely, unreasonable, or impractical based on your general knowledge.

Question: With reference to India’s climate, consider the following statements:

·         Most of India’s rainfall is received during the southwest monsoon.

·         The retreating monsoon contributes to more rainfall than the southwest monsoon.

Which of the statements given above is/are correct?

A) 1 only

B) 2 only

C) Both 1 and 2

D) Neither 1 nor 2

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Broad or Familiar Topics.

• The question is about India's climate and monsoon patterns, which are commonly discussed in general knowledge contexts. Even if you haven’t studied monsoons in detail, you likely know that the southwest monsoon is significant for India's weather.

Step 2: Focus on What Seems Logically Likely.

• Statement 1: "Most of India’s rainfall is received during the southwest monsoon." This seems logically correct because the southwest monsoon is widely known to bring heavy rains to India, especially during the summer months.
• Statement 2: "The retreating monsoon contributes to more rainfall than the southwest monsoon." This seems unlikely. The retreating monsoon is responsible for some rainfall, particularly in southern India (Tamil Nadu), but it’s not responsible for more rainfall than the southwest monsoon. This doesn’t align with what you may have heard in general discussions about Indian weather.

Step 3: Avoid Overcomplicating.

• You don’t need advanced meteorological knowledge here. The simpler and more common-sense option is that the southwest monsoon brings more rain.

Step 4: Eliminate Improbable Options.

• Since Statement 2 seems logically wrong, you can eliminate B (2 only) and C (Both 1 and 2).
• This leaves you with A (1 only) or D (Neither 1 nor 2).
• Since Statement 1 seems reasonable, choose A (1 only).

Final Answer: A (1 only).

Common Mistake:

• Some students might overthink the role of the retreating monsoon and assume it brings more rain, especially if they are unfamiliar with the specific climatic data. This might lead them to select B or C incorrectly.

Question: The term ‘Levant’ often heard in the news refers to a region roughly around:

A) The Horn of Africa

B) The Mediterranean coastlines

C) The area around the Persian Gulf

D) The region around the Caspian Sea

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Broad or Familiar Topics.

• The term Levant has been frequently used in global news, particularly in connection with conflicts in the Middle East. Even if you don’t know the exact geographic definition, you may have heard it in the context of the Mediterranean and the Middle East.

Step 2: Focus on What Seems Logically Likely.

1.        Option B (Mediterranean coastlines) seems like the most reasonable choice because the term Levant is historically associated with regions like Syria, Lebanon, Israel, and Jordan, all of which border the Mediterranean Sea.

2.        Option A (Horn of Africa), Option C (Persian Gulf), and Option D (Caspian Sea) are geographically far from the region typically referred to as the Levant.

Step 3: Avoid Overcomplicating.

• Even if you’re not sure, the Mediterranean is often in the news with the term Levant, especially in the context of historical and contemporary issues like the Syrian conflict. There's no need to overthink or associate it with regions far from the Mediterranean.

Step 4: Eliminate Improbable Options.

• Eliminate A (Horn of Africa), C (Persian Gulf), and D (Caspian Sea) because they are geographically irrelevant.
• The correct answer is B (The Mediterranean coastlines).

Final Answer: B (The Mediterranean coastlines).

Common Mistake:

• Students may confuse the Levant with regions like the Persian Gulf, leading them to select C. But focusing on the general geographic location associated with the term helps you use common sense here.

Question: Consider the following statements:

• The Global Ocean Commission is an international organization dedicated to conserving ocean ecosystems.
• The headquarters of the Global Ocean Commission is located in New Delhi.

Which of the statements given above is/are correct?

A) 1 only

B) 2 only

C) Both 1 and 2

D) Neither 1 nor 2

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Broad or Familiar Topics.

• The term Global Ocean Commission gives you a clue that it is likely related to ocean conservation. Even if you haven’t studied it in detail, you can apply basic reasoning about international organizations.

Step 2: Focus on What Seems Logically Likely.

1.        Statement 1: It is common sense that a body named the Global Ocean Commission would focus on conserving ocean ecosystems. Therefore, this seems likely to be true.

2.        Statement 2: It’s unlikely that the headquarters of a global organization focused on ocean conservation would be located in New Delhi, a landlocked city far from any ocean. Global environmental bodies are usually located in places more directly involved with their focus, like Geneva or coastal cities.

Step 3: Avoid Overcomplicating.

• You don’t need detailed knowledge of where the headquarters are located. It's sufficient to reason that a landlocked city like New Delhi is an unlikely location for an organization dedicated to the oceans.

Step 4: Eliminate Improbable Options.

• Since Statement 2 is unlikely, eliminate B (2 only) and C (Both 1 and 2).
• You’re left with A (1 only) and D (Neither 1 nor 2).
• Since Statement 1 is logically true, the correct answer is A (1 only).

Final Answer: A (1 only).

Common Mistake:

• Some students might not apply their reasoning about the location and might overthink the organization’s headquarters, leading them to incorrectly select C.

Question: Which of the following best describes the term ‘Green Hydrogen’?

A) Hydrogen gas obtained by heating green plants

B) Hydrogen gas produced using nuclear energy

C) Hydrogen gas generated from renewable energy sources like wind or solar power

D) Hydrogen gas produced by using fossil fuels

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Broad or Familiar Topics.

• The term “green” is often associated with environmentally friendly or sustainable energy sources. This should give you a hint that the term refers to something related to renewable energy.

Step 2: Focus on What Seems Logically Likely.

• Option C (renewable energy sources like wind or solar power) seems logically correct because "green" typically refers to clean energy like wind, solar, or other renewables.
• Option A (heating green plants) and Option D (fossil fuels) both seem contradictory to the idea of "green" energy.
• Option B (nuclear energy) doesn’t fit the common idea of "green" energy either, even though nuclear power has its own environmental benefits.

Step 3: Avoid Overcomplicating.

1.        Even if you don’t know what Green Hydrogen is, simply associating “green” with renewable energy helps guide your decision. Don't overthink by considering unlikely sources like fossil fuels or green plants.

Step 4: Eliminate Improbable Options.

• Eliminate A, B, and D because they don't logically align with the term "green" as it is commonly understood.
• The correct answer is C (Hydrogen gas generated from renewable energy sources like wind or solar power).

Final Answer: C (Hydrogen gas generated from renewable energy sources like wind or solar power).

Common Mistake:

• Some students might overthink and assume nuclear energy is considered "green" due to its low carbon emissions, leading them to select B. However, in the context of renewable energy, Option C is the most logical.

Question: With reference to Indian economy, consider the following statements:

• The government of India subsidizes the interest on loans taken by women under the ‘Stand-Up India Scheme’.
• Loans under the ‘Stand-Up India Scheme’ are only available to women.

Which of the statements given above is/are correct?

A) 1 only

B) 2 only

C) Both 1 and 2

D) Neither 1 nor 2

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Broad or Familiar Topics.

• The Stand-Up India Scheme is a widely publicized scheme aimed at supporting entrepreneurship. Even if you don’t know the details, you may have heard of it in the news or government announcements.

Step 2: Focus on What Seems Logically Likely.

• Statement 1: It’s reasonable to assume that the government provides interest subsidies for loans taken by women entrepreneurs, as similar schemes offer such benefits.
• Statement 2: It’s unlikely that loans under Stand-Up India are exclusively for women. Typically, government schemes provide support to multiple sections of society, and the Stand-Up India Scheme also caters to SC/ST communities and not just women. Therefore, Statement 2 is false.

Step 3: Avoid Overcomplicating.

• You don’t need detailed knowledge of the scheme to understand that government programs rarely target only one specific group, especially in a diverse country like India.

Step 4: Eliminate Improbable Options.

1.        Since Statement 2 is incorrect, eliminate B (2 only) and C (Both 1 and 2).

2.        You're left with A (1 only) and D (Neither 1 nor 2).

3.        Since Statement 1 seems logically true, choose A (1 only).

Final Answer: A (1 only).

Common Mistake:

• Some students may assume that the Stand-Up India Scheme is exclusive to women and incorrectly select C. However, common sense tells you that it would likely include other groups as well.

Question: With reference to everyday objects, which of the following best explains why glass windows are often cracked by thunderstorms?

A) Thunderstorms create vacuum pressure, which causes the glass to break.

B) Thunderstorms produce sudden changes in temperature, leading to rapid expansion and contraction of the glass.

C) The wind during thunderstorms contains high levels of dust particles that weaken the glass structure.

D) Thunderstorms produce ultraviolet light that makes the glass brittle.

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Familiar Concepts.

• The keyword is “glass windows cracking during thunderstorms”, which deals with common weather-related phenomena. Thunderstorms are associated with sudden changes in weather conditions.

Step 2: Use Logical Reasoning.

• Option A talks about vacuum pressure, which seems overly technical and unlikely to be the primary cause of cracking glass.
• Option B makes sense because rapid changes in temperature during thunderstorms can cause expansion and contraction in glass, which might lead to cracks.
• Option C refers to dust weakening the glass, which is less likely during a short event like a thunderstorm.
• Option D mentions ultraviolet light, which typically doesn't cause immediate damage to glass during thunderstorms.

Step 3: Choose the Most Logical Answer.

• The most logical explanation is Option B (sudden temperature changes cause expansion and contraction of the glass), which fits well with the physical properties of glass.

Final Answer: B (Thunderstorms produce sudden changes in temperature, leading to rapid expansion and contraction of the glass).

Question: Why do hot air balloons rise?

A) The gas inside the balloon becomes lighter as it heats up.

B) The hot air inside the balloon is less dense than the cooler air outside, causing the balloon to rise.

C) The atmosphere becomes thinner as the balloon ascends, reducing the air pressure and lifting the balloon.

D) The helium inside the balloon reacts with oxygen, creating upward force.

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Familiar Concepts.

• The key here is “hot air balloons rising”, a fairly common concept involving heat and air.

Step 2: Use Logical Reasoning.

• Option A says the gas becomes lighter, but gases don't change their intrinsic weight when heated.
• Option B suggests that hot air is less dense than the cooler air outside, which is correct. When air inside the balloon is heated, its density decreases, and the balloon rises.
• Option C refers to the atmosphere becoming thinner, but this doesn’t cause the balloon to rise.
• Option D talks about a helium reaction, but hot air balloons don’t use helium.

Step 3: Choose the Most Logical Answer.

• Option B (hot air is less dense than cooler air) is the correct explanation because it describes the principle of buoyancy in hot air balloons.

Final Answer: B (The hot air inside the balloon is less dense than the cooler air outside, causing the balloon to rise).

Question: Why do plants appear green to the human eye?

A) They absorb green light and reflect all other colours

B) They absorb all colours of light except green, which is reflected.

C) They only absorb blue and red light, which makes them appear green.

D) They absorb ultraviolet light, which causes green pigment to form in the leaves.

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Familiar Concepts.

• This question is asking why plants are green, something commonly taught in basic biology classes.

Step 2: Use Logical Reasoning.

• Option A says plants absorb green light, which would make them appear a different colour, so this is incorrect.
• Option B states that plants absorb all colours except green, which is correct. The green light is reflected, making plants appear green to our eyes.
• Option C has some truth, but it incorrectly implies that only blue and red light are absorbed.
• Option D is unrelated to the actual reason plants appear green.

Step 3: Choose the Most Logical Answer.

• The correct explanation is Option B (Plants absorb all colours except green, which is reflected).

Final Answer: B (They absorb all colours of light except green, which is reflected).

Question: Why is the sky blue during the day but appears red or orange during sunrise and sunset?

A) During the day, the atmosphere scatters all wavelengths of light, making the sky blue.

B) At sunrise and sunset, the light passes through a thicker layer of atmosphere, scattering shorter wavelengths and leaving red and orange to reach the observer.

C) The sky changes colour due to pollution levels, which increase at dawn and dusk.

D) The blue colour is due to the reflection of oceans, which becomes red as the sun moves lower.

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Familiar Concepts.

• This question relates to basic physics and light scattering. The key is understanding how light travels through the atmosphere.

Step 2: Use Logical Reasoning.

• Option A is incorrect because while scattering occurs, it doesn’t scatter all wavelengths equally.
• Option B correctly explains that light passes through a thicker layer of atmosphere during sunrise and sunset, scattering shorter wavelengths (blue and violet) and leaving longer wavelengths (red and orange) to reach the observer.
• Option C about pollution is incorrect because it’s not the main reason for colour changes.
• Option D (reflection of oceans) is a myth and incorrect.

Step 3: Choose the Most Logical Answer.

• The correct explanation is Option B (At sunrise and sunset, the light passes through a thicker layer of atmosphere, scattering shorter wavelengths and leaving red and orange to reach the observer).

Final Answer: B (At sunrise and sunset, the light passes through a thicker layer of atmosphere, scattering shorter wavelengths and leaving red and orange to reach the observer).

Question: Why do ice cubes float in water?

A) Ice has a higher density than water, so it floats.

B) The temperature of ice is lower than that of water, which makes it buoyant.

C) Ice has a lower density than water, allowing it to float.

D) Ice floats because it contains dissolved air, which makes it lighter than water.

Step-by-Step Application of General Knowledge or Common Sense:

Step 1: Identify Familiar Concepts.

• This is a simple question about buoyancy and the properties of ice and water.

Step 2: Use Logical Reasoning.

• Option A is incorrect because higher density objects sink, not float.
• Option B doesn’t make sense, as temperature alone doesn’t affect buoyancy.
• Option C is correct. Ice has a lower density than water because its molecular structure expands as it freezes, making it less dense and causing it to float.
• Option D introduces dissolved air, which isn't the reason why ice floats.

Step 3: Choose the Most Logical Answer.

• The correct explanation is Option C (Ice has a lower density than water, allowing it to float).

Final Answer: C (Ice has a lower density than water, allowing it to float)

The Use of General Knowledge or Common-Sense method is invaluable in the UPSC CSE Prelims when direct subject knowledge is lacking. This method works best when:

• You apply logic and reasoning based on what you know about the world.
• You eliminate improbable options that are factually unlikely or unreasonable.
• You use common sense to make the simplest and most practical choice.

With practice, this method can help you solve even the most challenging questions by leveraging your general awareness and reasoning skills.