CBSE ADDA

Question: 1.  Why do we prefer a convex mirror as a rear-view mirror in vehicles? Question: 2.  Name the mirror that can give an erect and enlarged image of an object? Question: 3.  What could be the position of the object if the image formed by a concave mirror is observed  to be virtual, erect and larger than the object? Question: 4.  Is the optical centre always at the centre of lens? Question: 5.  When the image formed is virtual and erect, what is the magnification,  positive or negative? Question: 6. When the image formed is real and inverted, what is the magnification,  positive or negative? Question: 7.  Is mirror formula valid only for the plane mirror? Question: 8.  Which light will refract more, a violet or red, if they pass through the same  glass slab with the  same angle of incident? Question: 9.  Does Snell’s law fail, if yes than when? Question: 10.  What is a lens?  Answers for above  Questions  Answer: 1.  Convex mirrors enable the

Class 09 Subject -Science Atoms and molecules Sample Test Paper Time 1 hr  M.M.35 (Section A) 10 x 1 = 10 1. The atomic radius of hydrogen atom is a. 0.037 nm b. 0.037 x 10 -9 m c. both a &b d. none 2. Complete the following sentence : In water, the proportion of hydrogen and oxygen is ---------- by mass a. 1:8 b. 3:4 c. 9:0 d. none 3. The actual mass of hydrogen atom a. 1.673 x 10 -24 g b. 1.673 x 10 c.1u d. both a & b 4. The symbol of cobalt a.C.o. b. CO c. Co. d. none 5. Atomicity of noble gases is one a. True b. false c. can’t say d none 6. The molecular mass of sulfuric acid a. 28 u b. 108 u c. 98u d. none 7. What are the number of electron and proton in chlorine ion a. 17p & 18 e b. 18 p & 17 e c. 17 e & 0 e d. none 8. The value of symbol ‘L’ a. 6.022 x 10 23 b. 6.02

1. If the pH of water is two, out of soap and detergent which one will you usefor cleaning clothes? (1) 1. Name the compound CH 3 COOC 2 H 5 .Name the acid and alcohol from which it is made .write equation. 2. An organic compound X with a molecular formula C 2 H 6 O undergoes oxidation with in presence of Alkaline   KMnO 4 to form a compound Y. X on heating in presence of conc. H 2 SO 4 at 443k gives Z which on reaction with H 2 O in presence of H 2 SO 4 gives back ‘X’ ‘Z’ reacts with Br 2 (aq) and decolorizes it. Identify X, Y &Z and write the reactions involved. (3) 3. An organic compound ‘A’ is widely used as a preservative in pickles and has a molecular formula C 2 H 2 O 2 .This compound reacts with ethanol to form a sweet smelling compound B. (i) Identify the compound A. (ii) Write the chemical equation for its reaction with ethanol to formcompound ‘B’ (iii) How can we get compound ‘A’ back from B? (iv)Name the process and write corresponding chemic

CBSE PHYSICS: 10th Science - Our Environment/Management of Natur... : Set-1Chapter - 15 Our Environment 1 mark questions :- 1. Write any one significance of biochemical cycles? 2. Define environment. 3. According to the sustenance from environment, organisms can be grouped into which three categories? 4. Name any two groups of producers. 5. Define consumers. 6. Write the two raw materials for making food, used by living organisms of first trophic level. 7. Explicate the principle of food web. 8. Which of the following are more numerous in a food chain :–(i) Secondary consumer (ii) Tertiary consumer 9. Define biological magnification. 10. Write the names of two decomposers. 11. Define global warming. 12. Write one ill effect of exposure to ultraviolet rays. 13. Which component of sunlight is vital for formation of ozone? 14. As a step to control pollution ‘Kulhads’ were used on a large scale. What was the ill effect of this practice? 15. A food chain consists of grass, lion and rabbit.

1. Application Procedure:  The online submission of particulars may be made at website www.ctet.nic.in. The candidates should supply all the required details while filling up the online form. On submission of details, a Confirmation page with Registration No. shall be generated. Candidates are required to take printout of Confirmation page and paste photograph, sign in the space earmarked for the purpose. The confirmation Page is to be sent by Registered/Speed Post to CBSE (NOT BY COURIER) to " The Assistant Secretary (CTET Unit), Central Board of Secondary Education, 'Shiksha Sadan', 17, Rouse Avenue, New Delhi - 110002" along with original Demand Draft (if fee paid by Demand Draft) for further processing so as to reach latest by 30.11.2011 . Application received beyond this date will not be accepted. Payment can be made as follows by Credit/Debit Card or Demand Draft in favour of the Secretary, Central Board of Secondary Education, Delhi drawn in any Nationalize

CARBON AND ITS COMPOUNDS F.A. - III-2011-12 TIME: 40 min.  Max. Marks. -40. 1. Name the compound formed on heating ethanol at 443 K with excess of conc. H2SO4.1 2. What happens when a small piece of sodium is dropped into ethanol?1 3. Write the chemical equation for the decarboxylation reaction of ethanoic acid.1 4. Give an example of esterification reaction.1 5. Name the product obtained when ethanol is oxidized by either chromic anhydride oralkaline Potassium per manganate. 1 6. Write the chemical equation representing the preparation reaction of ethanol from ethene.1 7. Name the two elements which are present both in CNG and petroleum.                     2 8. Draw the electronic dot structure of ethane molecule (C2H6).                                    2 9. Write the IUPAC name of the next homologue of CH3OHCH 2 CH3                         2 10. Define homologous series of organic compounds. Mention any two characteristics of homologous series.

Chapter - 8 How Do Organisms Reproduce Points to remember:- Q 1. What is the importance of DNA copying in reproduction? Ans. DNA contains information for inheritance of features from parents to next generation. DNA  present in the cell nucleus is the information source for making proteins. If the information is different,  different proteins will be made. Different proteins will eventually lead to altered body designs. Q 2. Why is variation beneficial to the species but not necessarily for the individual? Ans. Variations are useful for the survival of species in changed environmental situations. For  example, if a population of reproducing organisms were suited to a particular niche (well-defined  place of abode) and if the niche is drastically altered the population could be wiped out. However, if  some variations were to be present in a few individuals in these populations, there would be some  chance for them to survive. Thus if there were a population of bac