PHYSICS CH8 Sound — Science STD 9 — Question

Write the rules that are followed in writing the symbols of units in SI system.

Describe the construction and working of mercury barometer.

Identify the incorrect statement and correct them.

1. Like covalent compounds, coordinate compounds also contain charged particles (ions). So they are good conductors of electricity. 
2. Ionic bond is a weak bond when compared to Hydrogen bond.
3. Ionic or electrovalent bonds are formed by mutual sharing of electrons between atoms. 
4. Loss of electrons is called Oxidation and gain of electron is called Reduction.
5. The electrons which are not involved in bonding are called valence electrons.

Account the role of Radioactive isotopes in Diagnosis and treatment in the Medical field?

Differentiate graphite and diamond

What is an echo? Write the conditions to hear an echo.

The adjacent diagram shows the velocity-time graph of the body.
a) During what time interval is the motion of the body accelerated?b) Find the acceleration in the time Interval mentioned in part ‘a’.c) What is the distance travelled by the body in the time interval mentioned ¡n part ‘a’?

Mention the drawbacks of Nanomaterials in chemistry.

Explain Tyndall effect and Brownian movement with suitable diagram.