(a) Whi are wide wooden sleepers kept below railway lines?
(b) Whi does a balloon not collapse under atmospheric pressure?

Explain why, wooden (or concrete ) sleeps are kept below the railway line .

A small piece of iron is tied to a wooden block and the compound block so formed is immersed into a container filled with water, with iron piece above the wooden block. What will happen to the volume of wood submerged inside the water (a) the block is now inverted with iron piece below the wooden block? (b) if the whole arrangement is sealed and pressurised above atmospheric pressure.

Give reasons for the following statements: (a) Railway tracks are laid on large sized wooden sleepers. (b) It is difficult to walk on and. (c) Walking bare footed on a pebbled path is painful.

These questions consist two statements each, printed as Assertion and reason, while answering these question you are required to choose any one of the following four responsis: (a) If both the assertion and reason are true and reason is a true explanation of the assertion. (b) If both the assertion and reason are true but the reason is not the correct explanation of assertion. (c ) If the assertion is true but reason is false. (d) If both the assertion and reason are false. Q. Assertion: Railway tracks are laid on small-sized wooden sleepers. Reason: Small sized wooden sleepers are used so that rails exert more pressure on the railway track. due to which rail does not leave the track.

Which of the following does not affect water potential of Water ? (A) Concentration of dissolved substances (B) Atmospheric pressure (C) Gravitation (D) Capillarity