Put a nut in a cup. Float the cup in a jar of water and mark the
water level in the jar.
Punch a hole in the bottom of the cup and again put it in water.
Water starts entering the cup and it gradually sinks. Observe water
level in the jar while the cup is sinking and after it has sunk.
Now Answer
1. When the cup is sinking, water level in jar
(a) Increases (b) Decreases (c) Remains same
2. When the cup has sunk, water level is
(a) Increasing (b) Decreasing (c) Remains same
3. Name the principle on which this activity is based?
That's a kind thought Woofgang, I sometimes find it is quicker to do an empirical experiment rather than try to get an answer from theoretical considerations.