Question 1

What is the difference between renewable and non-renewable energy sources?

Accepted Answer

Renewable energy sources, like solar, wind, and hydro, are naturally replenished and have low carbon emissions, but they can be intermittent. Non-renewable sources, such as coal, oil, and gas, are finite and produce greenhouse gases, but they provide reliable, on-demand power. Nuclear energy is non-renewable but low-carbon. Your choice depends on factors like location, cost, and environmental goals.

Question 2

How do batteries store energy?

Accepted Answer

Batteries store energy chemically. In a rechargeable (secondary) battery, like lithium-ion, chemical reactions occur during charging to store energy, and during discharge, those reactions reverse to release electrical energy. Primary batteries (e.g., alkaline) are single-use because the chemical reaction is not reversible. The amount of energy stored is measured in watt-hours (Wh).

Question 3

What is energy efficiency and why is it important?

Accepted Answer

Energy efficiency is the ratio of useful output energy to total input energy, often expressed as a percentage. For example, an LED bulb converts about 90% of electrical energy into light, while an incandescent bulb converts only 10%. Higher efficiency means less wasted energy, lower costs, and reduced environmental impact. In design, choosing efficient components can improve product performance and sustainability.

Question 4

How do I choose the right energy source for a product?

Accepted Answer

Consider the product's power requirements, usage pattern, portability, cost, and environmental impact. For a portable device, a lightweight rechargeable battery is ideal. For a home heating system, natural gas or a heat pump might be better. Evaluate factors like energy density, lifespan, recharge time, and disposal. Always justify your choice with specific reasons in exams.

Question 5

What are the main types of energy storage?

Accepted Answer

Common types include batteries (chemical), capacitors (electrostatic), pumped hydro (gravitational potential), compressed air (pressure), flywheels (kinetic), and hydrogen fuel cells (chemical). Each has different characteristics: batteries have high energy density but limited cycles; capacitors charge quickly but store less energy; pumped hydro is large-scale but location-dependent. Choose based on application needs.

Question 6

How does energy generation affect the environment?

Accepted Answer

Non-renewable sources like coal and gas release CO2 and pollutants, contributing to climate change and air pollution. Nuclear produces radioactive waste. Renewables have lower emissions but can impact habitats (e.g., hydro dams) or use rare materials (e.g., solar panels). Storage technologies also have environmental costs from mining and disposal. A life cycle assessment helps compare overall impacts.

How energy is generated and stored in order to choose and use appropriate sources to make products and power systems

Topic Overview

Key Concepts

What You Need to Demonstrate

Marking Points

Examiner Tips

Common Mistakes

Frequently Asked Questions

Before You Start

Likely Command Words

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