Question

Which of the following is/are FALSE:

• A. A balloon collapses when air is removed from it.
• B. Water does not run out of a dropper unless its rubber bulb is pressed.
• C. Two holes are made in a sealed tin can to take out oil from it.
• D. None

Answer 1

The correct option is D None

(i) A balloon collapses when air is removed from it.
Because air inside the ballon occupies some space and when air is removed from the ballon it collapses as there is no air inside the ballon.Also, air exerts some pressure on the walls of the ballon. This pressure balances the contraction of the ballon. When air is removed from the ballon, there is no such pressure and the ballon collapses.
(ii) Water does not run out of a dropper unless its rubber bulb is pressed.
when filling up dropper u pess it which means u are pushing out all the air inside the dropper ..meanin u r creating vacuum...now pressure diff is created and water rusher in so that the pressure inside the dropper equals atmospheric pressure...now as there is no pressure diff,the water stays inside dropper...now to take out the water u need to appl ext pressure ie pressure in dropper so that high pressure is created on water and naturally the pressure outside the dropper is low...thus water rushes out...
(iii) Two holes are made in a sealed tin can to take out oil from it.
If you only have one hole, liquid will flow out slower because air will need to replace the liquid inside the can, and the same hole the liquid flows out of is where air will go in. If you have two holes, the oil can continuously flow out one whole while air continuously goes into the
other hole. And since it's oil, the hole needs to be bigger because of the higher viscosity (thickness) than water or juice.