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Fill in the following blanks with suitable words :
A solar cell converts …………………. energy into …………………. energy.
solar energy into electrical energy.
A hydro-power plant converts one from of energy into another. Name the two forms of energy.
What type of energy is possessed by flowing water?
Flowing water can rotate a turbine. Which type of energy is used up by the turbine?
Name the original source of wind energy.
What should be the minimum wind speed for the satisfactory working of a wind- powered electric generator?
Write one use of wind energy
(a) In the past
(b) At present.
Why is the copper tube of a solar water heater painted black from outside?
What type of reactions occurring inside the sun produces solar energy?
Name some of the solar energy devices.
What type of reflector is used in a box-type solar cooker?
What is the range of temperature which can be achieved in a box-type solarcooker in two to three hours?
Name the devices which converts sunlight into electricity.
How much solar energy will be received by 1 m2 area in one hour if the solar constant be 1.4 kW/m2?