Gravitation — Science STD 9 — Question

The substance X normally exists in a physical state which can flow easily but does not fill its vessel completely. It also turns anhydrous copper sulphate blue. When substance X is cooled excessively, it changes into a substance Y which has a fixed shape as well as a fixed volume. If, however, the substance X is heated strongly, it changes into a substance Z which has neither a fixed shape nor a fixed volume.

1. Name the substances (i) X (ii) Y and (iii) Z.
2. What is the process of conversion of X into Y known as?
3. At which temperature X gets converted into Y?
4. What is the process of conversion of X into Z known as?
5. At which temperature X gets converted into Z?

What is the meaning of the symbol kWh? What quantity does it  represent?

Enlist the conclusions drawn by Rutherford from his α-ray scattering experiment.

When water is drawn from a well, a bucket feels heavier when it is drawn out of water or in the air than inside water. Why?

What are the functions of bones, cartilages, ligaments and tendons?

Define momentum of a body. On what factors does the momentum of a body depend?

Name the tissue, which helps in transportation of oxygen that we inhale to various parts of the body. Write the composition of this tissue.

How is melting point related to intermolecular forces of attraction? Why is latent heat of vaporization higher than latent heat of fusion?

When we put our ear to a railway line, we can hear the sound of an approaching train even when the  train is far off but its sound cannot be heard through the air. Why?