General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
181
The term “PM2.5” refers to particles:
Answer:
≤2.5 μm
These fine particles penetrate deep into lungs and enter the bloodstream. Major sources include combustion and secondary formation. Health risks include cardiovascular and respiratory disease.
---
182
A common co-benefit of energy efficiency is:
Answer:
Reduced emissions and improved comfort
Efficiency cuts fuel use and emissions, lowering bills. Better controls and insulation improve thermal comfort. Proper ventilation maintains IAQ.
---
183
The best household practice to cut potable water use is:
Answer:
est household practice to cut potable water use is:
Efficient taps, toilets, and showerheads significantly reduce consumption. Leak repair saves continuous losses. Behavioral changes complement hardware upgrades.
---
184
A major risk of large-scale biofuel expansion is:
Answer:
Land-use change and habitat loss
Converting forests/grasslands for biofuel crops releases carbon and reduces biodiversity. Indirect land-use change can offset GHG benefits. Sustainable sourcing is critical.
---
185
A “rain garden” mainly helps to:
Answer:
Infiltrate and treat stormwater onsite
Depressed, vegetated areas capture roof/driveway runoff, filtering pollutants. They reduce flooding and protect streams. Native plants improve performance and habitat.
---
186
A circular economy prioritizes:
Answer:
Material loops, reuse, and regeneration
It aims to keep materials in use at high value, minimizing waste and emissions. Design for durability and recycling is central. It contrasts with linear models.
---
187
The primary cause of eutrophication in lakes is excess:
Answer:
ause of eutrophication in lakes is excess:
Nutrient enrichment fuels algal blooms that reduce dissolved oxygen. Common sources are agriculture and sewage. Control focuses on N/P reduction.
---
188
The largest reservoir in the hydrologic cycle is:
Answer:
ycle is:
Oceans hold about 97% of Earth’s water. Atmosphere and rivers contain tiny fractions. Groundwater is the largest freshwater reservoir after ice.
---
189
The main purpose of an Environmental Management System (EMS) like ISO 14001 is to:
Answer:
Provide a framework for continual environmental improvement
EMS structures policy, planning, implementation, checking, and review. It emphasizes compliance and performance enhancement. Certification signals systematic management.
---
190
The primary reason to install variable frequency drives (VFDs) on motors is to:
Answer:
Match motor speed to load and save energy
Affinity laws mean small speed reductions yield large energy savings in fans and pumps. VFDs also soften starts and extend equipment life. They are central to industrial efficiency.
---