Physics X - Chapter 15: Our Environment
Solve Our Environment MCQs for Class 10 Science. Learn ecosystems, food chains, pollution, waste management, and conservation.
Quick Revision : Our Environment
- Ecosystem: Interaction of biotic (living) and abiotic (non-living) components in an area.
- Biotic Components: Producers, consumers, decomposers.
- Producers (Autotrophs): Green plants – convert solar energy to chemical energy via photosynthesis.
- Consumers (Heterotrophs): Herbivores (primary), carnivores (secondary/tertiary), omnivores, parasites.
- Decomposers: Bacteria/fungi – break down dead matter, recycle nutrients.
- Food Chain: Linear sequence of who eats whom (e.g., Grass → Grasshopper → Frog).
- Trophic Levels: Steps in a food chain (Producers → Primary → Secondary → Tertiary consumers).
- 10% Law (Lindeman's Law): Only ~10% energy transferred to next trophic level; rest lost as heat/metabolism.
- Food Web: Network of interconnected food chains; increases ecosystem stability.
- Energy Flow: Unidirectional (Sun → Producers → Consumers → Decomposers).
- Nutrient Cycling: Cyclic flow of nutrients (C, N, P) via biogeochemical cycles.
- Biodegradable Waste: Can be decomposed by microbes (e.g., paper, vegetable peels).
- Non-biodegradable Waste: Cannot be decomposed (e.g., plastic, metals, glass).
- Biological Magnification: Increase in concentration of non-biodegradable chemicals at higher trophic levels (e.g., DDT in birds).
- Ozone Layer (O₃): In stratosphere; absorbs harmful UV radiation.
- Ozone Depletion: Caused by CFCs, halons; leads to ozone hole, increased UV exposure.
- Effects of Ozone Depletion: Skin cancer, cataracts, reduced phytoplankton, crop damage.
- Montreal Protocol (1987): International treaty to phase out ozone-depleting substances.
- Waste Management: Reduce, Reuse, Recycle (3 R’s); composting, safe disposal.
- Ecosystem Types: Natural (forest, pond) and artificial (garden, aquarium).
Basic Level Questions
Chapter Summary : Our Environment
Chapter 15 - Our Environment, connects you to the invisible web of life that sustains our planet. It explains how energy flows and nutrients cycle through ecosystems, why some wastes vanish while others pile up for centuries, and how human actions—from using pesticides to discarding plastics—ripple through food chains and even damage the protective ozone shield far above us. This chapter transforms everyday observations into profound ecological understanding.
This chapter is a high-scoring unit in board exams and competitive tests like NTSE and Olympiads. It includes diagram-based questions (food chains/webs), numerical problems on energy transfer (10% law), and concept explanations (ozone depletion, biological magnification). Questions often ask you to compare biodegradable vs. non-biodegradable materials, analyze human impact on ecosystems, and suggest eco-friendly practices. Mastering this chapter helps you tackle both theoretical understanding and application-based problems with confidence.
Our platform turns ecological concepts into exam-ready knowledge. We offer a structured set of MCQs—from basic definitions to advanced calculations and real-world scenario analysis—that align perfectly with NCERT standards. By practicing here, you reinforce trophic level dynamics, energy transfer calculations, and environmental issue analysis. This targeted preparation builds conceptual clarity, improves problem-solving speed, and ensures you can confidently answer any board or competitive exam question, transforming complex ecology into easy marks.