Glass panes usually appear hazy because:
Water vapour settling on the tiny dust particles
Of chemical reactions
It is property of all transparent substances
They are old
The humidity of a place:
Lies between 10% to 20%
Is always more than 50%
Is always less than 80%
Varies from time to time
When we heat water, we can find bubbles coming from it. This shows that:
Water contains air
Air contains water
Hot water becomes bubbles
None of these
Which of the following are the uses of air?
Generating electricity
Disposal of seeds
Flying of birds
All of these
All the plants require nitrogen for:
Reproduction
Photosynthesis
Transpiration
Growth
Smoke is an example of:
Liquid-in-gas mixture
Gas-in-solid mixture
Solid-in-gas mixture
Gas-in-liquid mixture
Which of the following can show the direction of wind?
Anemometer
Wind vane
Wind mill
Barometer
The correct ascending order of gases as per their composition in air is:
Oxygen < carbon dioxide < nitrogen
Hydrogen < oxygen < nitrogen
Nitrogen < hydrogen < oxygen
Oxygen < Carbon dioxide < hydrogen
We can find tiny droplets of water on the outer surface of a steel glass containing cold water or ice. This shows that:
Steel contains air
Air contains water vapour
Cold water can seep through solids
Which of the following plays a very important role in the oxygen cycle ?
Birds
Animals
Plants
Soil
