Atoms and Molecules — Science STD 9 — Question

A disused railway line has a length of 300m. A man puts his ear against one end of the rail and another man hits the other end with a metal hammer. Sound travels at 5000m/ s in steel. The time it takes for the sound to travel along the rail is:

One of the following does not undergo sublimation. This one is:

1. Camphor.
2. Dry ice.
3. Silica.
4. Iodine.

A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because,

The branch which deals with the study of cell structure and function is known as:

Who reported that entity of an organism is not because of the cell but collection of many cells?

Which of the following helps in repair of tissue and fills up the space inside the organ?

The unit of measuring momentum of a moving body is:

Rinku and Pinku had half day schools during summer. They used to go to school by autorickshaw. They observed that the auto driver covered the top of the vehicle by some mats and sprinkled water on them regularly, which keeps it cool. Which of the following phenomena is involved here:

A 15% alcohol solution means: