psychologicalblogspot

1. (a) In an AP, if a = 50, d = -4 and Sn= 0, then find the value of n.   OR   (b) Find the sum of the first twelve 2-digit multiples of 7, using an AP.  solution:  OR 2. A solid metallic sphere of radius 3 cm is melted and recast into the shape of a solid cylinder of radius 2 cm. Find the height of the cylinder.  SOLUTION:  3. (a) Find the nature of the roots of the quadratic equation   x2-5x + 9 = 0 OR   (b) Write a quadratic equation with roots -3 and 5.  SOLUTION:  OR 4. Find the mode of the following frequency distribution:  SOLUTION: 

1. Humans have innate immunity to protect against pathogens that may enter the gut and food. What are the two barriers that protect the body from such pathogens? explanation: 1. skin- mechanical barrier retard entry of microbes. it has an acidic environment pH of about 3-5 which retards the growth of microbes. 2. mucous membrane: the conjunctivae and the alimentary respiratory and urogenital tract are lined by mucous membranes which wash away invading pathogens. mucous membrane release mucus which has antiviral and antibacterial substances. 2. A patient admitted to ICU was diagnosed to have suffered from myocardial infarction. The condition of the coronary artery is depicted in the image below. Name two bioactive agents and their mode of action that can improve this condition. OR Substantiate by giving two reasons why a holistic understanding of flora and fauna of the cropland is required before introducing an appropriate biocontrol method. explanation: to improve the patient's con...

1. (a) Draw two different possible structures of a saturated hydrocarbon having four carbon atoms in its molecule. What are these two structures of the hydrocarbon having same molecular formula called? Write the molecular formula and the common name of this compound. Also, write the molecular formula of its alkyne.  OR  (b) (i) Write the molecular formula of benzene and draw its structure.   (ii) Write the number of single and double covalent bonds present in a molecule of benzene.   (iii) Which compounds are called alkynes?  Explanation: two possible structures of hydrocarban these structures are called isomers. isomers have the same molecular formula but different structural arrangements. the molecular formula of the alkyne is  OR i) the molecular formula of benzene is  C6H6 ii) there are double bonds and nine single bonds in benzene. iii) Alkynes are organic molecules made of the functional group carbon-carbon triple bonds and are wri...