a piece of ice is floating in a beaker containing water. when the ice melts .the temperature falls from 20degree C to 4 degree C and the level of water

a)remains unchanged

b)falls

c)rises

d)change erratically

The mass of ice lost during melting = mass of water displaced by the ice cube

Therefore, after complete melting of ice, the level of water remains the same.

But since the final temperature of water is 4 degree Celcius, the volume of water will decrease for the same mass as density of water is highest at 4 degree Celcius.

Thus, the level of water falls.