Two bodies at different temperatures are placed in contact. State the direction in which heat will flow
Describe an experiment to show that water has maximum density at 4℃. What important consequences follow from this peculiar property of water? Discuss the importance of this phenomenon in nature.
State the volume changes observed when a given mass of water is heated from 0℃ to 10℃.
Sketch a temperature-volume graph to show the behavior
Draw a graph to show the variation in the density of water with temperature in the temperature range from 0℃ to 10℃.
A given mass of water is cooled from 10℃ to 0℃. State the volume changes observed.
Represent these changes on a temperature-volume graph.
A deep pond of water has its top layer frozen during the water. State the expected temperature of the water layer (i) just in contact with ice, (ii) at the bottom of the pond.
Explain the following:
(a) Water pipes in colder countries often burst in winter.
(b) In winter, the water tank (or ocean) starts freezing from the surface and not from the bottom
(c) Fishes survive in ponds even when the atmospheric temperature is below 0℃
(d) A hollow glass sphere that floats with its entire volume submerged in water at 4℃ sinks when water is heated above 4℃.
(e) A glass bottle completely filled with water and tightly closed at room temperature, is likely to burst when kept in the freezer of a refrigerator.
Water is cooled from 4℃ to 0℃. It:
(c) First contracts, then expands
(d) First expands, then contracts
Draw a diagram to show that the energy flow in an ecosystem is governed by the law of
conservation of energy
Energy enters in a food chain through:
(a) Primary consumers
(b) Secondary consumers
(c) Tertiary consumers
Name the two groups in which various sources of energy are classified. State on what basis are they classified
What is meant by renewable and non-renewable sources of energy? State two differences between them, giving two examples of each,
Select the renewable and non-renewable sources of energy from the following:
What is a solar cell? State two uses of solar cells. State whether a solar cell produces a.c. or d.c. Give one disadvantage of using a solar cell
What is wind energy? How is wind energy used to produce electricity? How much electric power is generated in India using wind energy?
What is hydro energy? Explain the principle of generating electricity from hydro energy.
How much hydro electric power is generated in India
What percentage of total electrical power generated in India is obtained from nuclear power plants? Name two places in India where electricity is generated from nuclear power plants?
State the energy transformation in the following:
(i) Electricity is obtained from solar energy
(ii) Electricity is obtained from wind energy
(iii) Electricity is obtained from hydroelectricity
(iv) Electricity is obtained from nuclear electricity
Which of the following solar radiations pass through the atmosphere of the earth?
X-rays, ultraviolet rays, visible light rays, infrared radiation
What would have been the temperature of the earth’s atmosphere in absence of green house gases in it?
The increase of carbon dioxide gas in atmosphere will cause:
(a) Decrease in temperature
(b) Increase in temperature
(c) No change in temperature
(d) Increase in humidity
Without the greenhouse effect, the average temperature of the earth’s surface would have been:
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