🌍 Global Challenges Flashcards
(10 cards)
What is red-shift, and what does it indicate about the universe?
Red-shift is the increase in wavelength of light from distant galaxies, indicating that the universe is expanding.
What is the Big Bang theory?
The theory that the universe began from an extremely dense and hot state and has been expanding ever since.
What is the role of the National Grid?
To distribute electricity from power stations to homes and businesses across the country.
Why is high voltage used in power transmission?
To reduce energy loss as heat in transmission lines;
Power loss ∝ current² × resistance.
What is the function of transformers in the National Grid?
Step-up transformers increase voltage for transmission; step-down transformers decrease voltage for safe usage.
What are some challenges of using renewable energy sources?
Intermittency, high initial costs, and the need for energy storage solutions.
How does increased carbon dioxide affect the Earth’s climate?
It enhances the greenhouse effect, leading to global warming and climate change.
What are some methods to reduce carbon emissions?
Using renewable energy, improving energy efficiency, and implementing carbon capture technologies.
What is the significance of typical speeds in physics?
They provide reference values for estimating and comparing the motion of different objects.
How can reaction time affect stopping distance?
Longer reaction times increase the thinking distance, thereby increasing the total stopping distance.
