Q. 1. why is dna copying essential for reproduction?

Q. 2. what is the role of a catalyst in a chemical reaction?

Q. 3. which class of compounds gives a positibve fehling’s test? Ans:aldehydes

Q. 4. what is meant by 1 volt?

Q. 5. write the chemical name and formula for bleaching powder?

Q. 6. What is meant by dehydrating agent?

Q. 7. state ohm’s law.draw a schematic diagram of the circuit for studying ohm’s law?

Q. 8. state one limitation for the usage of solar energy?

Q. 9. what is a gene and where is it located?

Q. 10. explain double fertilization in plants?

Q. 11. What is meant by magnetic field?

Q. 12. why chlorophyll green in colour?

Q. 13. give two methods to prevent rusting?

Q. 14. state the functions of gastric glands? 15.explain why stars twinkle?

Paper By Geetha
Email Id : aasritha2006@yahoo.co.in

Q.1. What is meant by thermal decomposition?

Q.2. Name the group of chemical substances used to prevent oxidation.

Q.3. What is the nature of oxides formed by metals and non metals?

Q.4. Name one cheap reducing agent commonly used in extraction of pure metals.

Q.5. Define catenation.

Q.6. Name the gas evolved when sodium carbonate or sodium bicarbonate reacts with ethanoic acid?

Q.7. Name the cells which regulate the opening and closing of stomata.

Q.8. Name the enzyme responsible for changing starch to sugar in mouth.

Q.9. What is scum?

Q.10. Which type of flame is produced by saturated hydrocarbons on incomplete combustion?

Q.11. What happens when calcium oxide reacts with water? Write the chemical equation of reaction involved.

Q.12. Respiration is considered an exothermic reaction. Explain?

Q.13. Give reason:- Ionic compounds conduct electricity only in molten state not in solid state.

Q.14. Explain why:-

Aluminium is more reactive than Iron, yet its corrosion is less than Iron.
Carbonate and sulphide ores are usually converted into oxides before reduction during process of e extraction.
Q.15. What is hydrogenation? Write its industrial application.

Q.16. Write the common name of ethanoic acid. What is its ditute solution (5-8%) in water known as?

Q.17. Write the functions of muscular wall in digestive tract.

Q.18. Why danger signals are red?

Q.19. Explain the phenomenon which causes twinkling of star.

Q. 20. An object of 4cm height is placed at a distance of 15cm away from a convex lens of focal length 10cm.
Find the nature, size, position of the object. Find its magnification.

Q. 21. Draw and explain the ray diagram formed by a convex mirror when

object is at infinity.
object is at finite distance from the mirror.
Q. 22. Name three refractive defects of vision with the help of diagram. Explain the reasons and correction of these d defects.

Q. 23. Describe the urine formation in human beings. Draw a neat and labelled diagram of nephron.

Q. 24. What are soaps? Explain the mechanism of the cleaning action of soaps? Soaps form scum (insoluble s substance) with hard water. Explain why? How this problem is overcome by use of detergents?

Q. 25. What are ionic compounds. State four properties of ionic compounds in respect to their physical nature, melting and boiling points, solubility and conduction of electricity?