Lime water turns milky when exposed to air and stirred. This shows that air contains:
Carbon dioxide
Hydrogen
Nitrogen
Oxygen
It is not proper to breathe through our mouth because:
The dust particles would enter our bodies
More carbon dioxide will be inhaled
Our throat will become sore
We will catch cold easily
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 plays a very important role in the oxygen cycle ?
Birds
Animals
Plants
Soil
Which of the following can show the direction of wind?
Anemometer
Wind vane
Wind mill
Barometer
Which of the following plays an important part while drinking a liquid with a straw?
Humidity
Temperature
Atmospheric pressure
Composition of air
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
None of these
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
Mountaineers carry oxygen cylinders with them because:
Oxygen supports combustion
Air becomes thinner as we go higher
Air is dense but lacks oxygen in mountains
The percentage of nitrogen in air is:
21%
0.1%
54%
78%
