Contribute & Test Your Skills
- Chemical Reactions & Equations
- Acid, Bases & Salts
- Metals & Non Metals
- Carbon & Its Compounds
- Periodic Classification of Elements
- Life Processes
- Respiration
- Control and Coordination
- How Do Organism Reproduce
- Heredity and Evolution
- Light: Reflection and Refraction
- Human Eye and Colorful World
- Electricity
- Magnetic Effect of Electric Current
- Sources of Energy
- Our Environment
- Management of Natural Resources
Popular Questions
- What is the basic cause for winds to blow? Name a part of India, where energy is commercially harnessed.
- Bio-gas is considered to be a boon to the farmers. Give reasons
- 100 W/m2 of solar energy is received by the Earth
- While filling LPG in cylinders, a substance X is added to make the detection of leakage of LPG from th cylinder easy.
- The Government of Delhi and Delhi Transport Corporation (DTC) have converted passenger buses into CNG based vehicles.
- Assertion : solar cells are used to convert solar energy into electrical energy.
- Assertion : Solar cooker is a device used to cook food Reason : Solar cooker can be used to cook food on cloudy days
- Firewood is a conventional fuel. list any four reasons for replacing it
- What are the environmental consequences of using fossil fuels? Suggest the steps
- Name the kind of energy possessed by wind and the device used to hardness it.
- Draw a well labelled diagram of a bio-gas plant.
- Define the process of nuclear fission.
- Assertion : Concave mirror is suited for use in a solar cooker. Reason : Concave mirror converges large amount of light of the sun..
- Give one disadvantage of nuclear power.
- Justify in one sentence that hydro power (hydro electricity) is a renewable source of energy.
- Name any two devices used to harness solar energy.
- Write the energy conversion that takes place in a hydropower plant.
- Why is there so much emphasis on changing over from petrol/diesel
- Write two different ways of harnessing energy from ocean.
- Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel
- Name two dams whose construction was opposed by local people.
- A certain form of energy is available due to the difference in the temperature of water at the surface of the ocean and its deeper..
- Name two combustible components of bio-gas.
- Assertion : Certain gases like carbon-dioxide, Reason : These gases are responsible for
- Solar energy can be harnessed directly as well as indirectly.
- Name any two energy sources that you would consider to be renewable.
- The solar constant at a place is 1.4 kW/m2. How much solar energy will be received at this place per second over on area of 5 m2?
- Name the type of reaction in the sun which produces its energy.
- Assertion : Charcoal is a better fuel than wood Reason : It has a lower heat generated efficiency
- Assertion : Wind energy is an environment friendly and efficient of energy. Reason : Wind energy farms can be established everywhe..
- What is a good source of energy?
- What is the cause of release of unusually large energies in nuclear fission reaction? How is the energy per fission calculated?
- How is the increase in demand for energy affecting our environment adversely?
- What are the advantages of nuclear energy?
- Can any source of energy be pollution free? Why or Why not?
- Acid rain happens because
- What are the disadvantages of fossil fuels?
- Which of the following is a non-renewable source of energy?
- Fuel used in thermal power plants is
- In a hydroelectric power plant more electrical power can we
