SUBJECT: SCIENCE
PHYSICS
1. What is the average atmospheric pressure on the surface of earth?
2. The unit kg m-ls-2 represent which physical quantity ?
3. Why do fountain pen leak on higher altitudes ?
4. How many forces acting on flying aero plane?
5. Why it is difficult to swim in sea water compare to lake water?
CHEMISTRY
1. What happens when a copper vessel is exposed to moist air for long tim
Answers
Answer :
1 )The average atomic pressure on the surface of the earth is '1atm'.
2) The unit kg m/s-2 represents the physical quantity 'force '.
3) It is due to the low atmospheric pressure on higher altitudes .
4) There are four forces acting on the flying aeroplane : drag , gravitational force of the earth , thrust and the upward acting force .
5) It is more easier to swim in sea water as compared to Lake water because sea water contains large amounts of dissolved salts which make it denser than the lake water and hence , we get more upthrust and we sink less in sea water . That is why it is difficult to swim in lake water than sea water .
Chemistry
1) When a copper vessel is exposed to moist air for a long time then it makes a greenish layer of basic copper hydroxide .
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