HOTS Questions: Energy—How Things Work | Our Wondrous World Class 5 - New NCERT PDF Download

Q1: If solar panels replace coal plants, evaluate the environmental benefits versus initial costs.
(a) No long-term savings
(b) Higher pollution from manufacturing
(c) Increased fossil fuel dependency
(d) Reduced emissions but high setup expenses
Ans: (d)
Explanation: Solar panels use sunlight to make clean electricity, unlike coal plants that puff out dirty smoke, harming the air. 
Setting them up costs a lot because panels and wires are pricey. 
Once ready, they give free power from the sun every day. 
This keeps our planet’s air fresh and fights warming.

Q2: Analyse why wind energy is sustainable in coastal areas.
(a) Steady breezes provide reliable power
(b) It requires calm weather
(c) It pollutes more than solar
(d) Winds are inconsistent there
Ans: (a)
Explanation: Coastal areas have strong, steady sea breezes that spin wind turbines to make electricity. 
Wind is free, never runs out, and doesn’t make smoky pollution like coal. 
Turbines turn breezes into power for homes and schools. 
This clean energy helps keep the coast green and sustainable.

Q3: Propose how Vaastu Shastra promotes energy efficiency in buildings.
(a) It increases artificial lighting needs
(b) It optimises sunlight and ventilation
(c) It ignores natural elements
(d) It focuses on aesthetics only
Ans: (b)
Explanation: Vaastu Shastra plans homes to catch sunlight through windows for brightness. 
It also uses cool breezes to keep rooms fresh without fans. 
This saves electricity by relying on nature’s light and air. 
Homes feel nice and use less power the smart way.

Q4: If batteries store energy, evaluate their role in renewable systems.
(a) They increase emissions
(b) They are non-rechargeable
(c) They provide power during low production periods
(d) They waste energy through leakage
Ans: (c)
Explanation: Batteries save extra energy from sunny or windy days in a special box. 
They give power to lights when it’s dark or calm outside. 
This makes clean energy from the sun and wind work all the time. 
It’s like a backup jar keeping electricity ready for us.

Q5: Compare kinetic energy in watermills to potential energy in dams.
(a) Watermills store energy
(b) Dams use kinetic energy only
(c) Kinetic from flow, potential from stored height
(d) Both are static
Ans: (c)
Explanation: Watermills use the fast flow of rivers to spin wheels, powering tasks like grinding grain. 
Dams hold water high in a lake, letting it rush down to spin turbines. 
Watermills need moving water’s energy, while dams use the stored water’s drop. 
Both turn water’s power into work for people.

Q6: Why are LEDs more efficient than incandescent bulbs?
(a) They use more power
(b) They produce more heat
(c) They last shorter
(d) They convert more electricity to light, less to heat
Ans: (d)
Explanation: 

LEDs make bright light using very little electricity, unlike old bulbs that waste power. They stay cool, not hot, so energy goes to light, not heat. This saves money on power bills for homes. LEDs are a green choice for bright, long-lasting lights.

Q7: Evaluate the safety risks of electricity without proper rules.
(a) It reduces usage
(b) It improves conductivity
(c) No dangers exist
(d) Shocks, fires from mishandling
Ans: (d)
Explanation: Without safety rules, touching loose wires can give painful electric shocks. 
Wrong setups might spark fires in houses or schools. 
Rules like covering wires with plastic keep us safe. 
Following them stops accidents and protects kids and families.

Q8: Analyse how food provides energy for living things.
(a) It replaces sunlight directly
(b) It has no caloric value
(c) It fuels cellular processes for movement and growth
(d) It stores indefinitely without intake
Ans: (c)
Explanation: Food gives animals energy from calories to jump, play, and grow strong. 
It powers tiny parts inside our bodies, like little engines, for daily tasks. 
Without food, we’d feel weak and tired fast. 
Eating healthy keeps us active and happy every day.

Q9: Propose why clean energy sources are crucial for climate change mitigation.
(a) They reduce emissions compared to fossils
(b) They require more land
(c) They are non-renewable
(d) They increase greenhouse gases
Ans: (a)
Explanation: Clean energy like sun and wind doesn’t make dirty gases that heat the planet. 
Unlike coal, they keep the air clean, slowing down climate change. 
They use free sunlight and breezes for power. 
This protects nature, animals, and our Earth’s future.

Q10: Compare solar and wind energy's intermittency challenges.
(a) Solar depends on daylight, wind on weather
(b) Solar works at night
(c) Wind is daytime-only
(d) Both are constant
Ans: (a)
Explanation: Solar power needs bright sunlight and stops at night or on cloudy days. 
Wind power needs strong breezes to spin turbines, which can slow down. 
Both can pause, so we store extra energy for later. 
They’re clean but need planning to work all the time.

Q11: Why does the brain use energy even at rest?
(a) It shuts down completely
(b) It maintains basic functions like thinking
(c) It requires movement
(d) It stores no energy
Ans: (b)
Explanation: Your brain uses food energy even when you’re resting to keep working. 
It controls breathing, heartbeats, and dreams without stopping. 
This energy comes from the meals you eat daily. 
The brain stays busy to keep your body running smoothly.

Q12: Evaluate animal heat in Ladakh homes for sustainability.
(a) It requires electricity
(b) It cools houses
(c) It provides natural warmth without fuel
(d) It increases pollution
Ans: (c)
Explanation: In chilly Ladakh, yaks and goats share body heat to warm homes at night. 
This natural warmth means less wood or gas is burned for heat. 
It’s an eco-friendly trick to stay cosy in winter. 
Animals help keep houses warm without harming the planet.

Q13: Propose how energy efficiency, like LEDs, contributes to conservation.
(a) By increasing waste
(b) By shortening lifespan
(c) By using more electricity
(d) By reducing consumption and bills
Ans: (d)
Explanation: LEDs light up rooms using way less electricity than old bulbs. 
They save energy, cutting down power plant use and bills. 
This helps conserve nature’s resources for everyone. 
Using LEDs is a simple way to care for Earth.

Q14: Analyse kinetic energy in windmills.
(a) It produces sound only
(b) It is stored wind
(c) Wind's motion turns turbines for electricity
(d) It requires stillness
Ans: (c)
Explanation: Wind’s fast movement pushes windmill blades to spin and make electricity. 
This captures wind’s energy to light homes without burning fuel. 
It’s a clean way to use nature’s breezes. 
Windmills turn the air’s speed into power for us.

Q15: If fossil fuels deplete, predict renewable energy's role in future supply.
(a) It will become obsolete
(b) It harms the environment more
(c) It will provide unlimited, clean alternatives
(d) It increases costs permanently
Ans: (c)
Explanation: When coal and oil run low, the sun and wind offer endless clean energy. 
They power homes without making dirty air like fossils do. 
This keeps the lights on and the Earth healthy. 
Renewables are a bright, green future for energy.