CBSE ADDA

Q. What is supernatant liquid ? Ans: A clear liquid that collected by decantation is called supernatant liquid. Q. Define loading. Ans : The process of increasing the rate of sedimentation ion by adding potash alum (fitkiri)  to it is called loading. Sometimes very fine solid particles do not sink to the bottom during sedimentation. By adding potash alum impurities became heavier and settle down .eg. muddy water, cleaning of river water . Q. What is Filtration? Ans: Filtration is a separation technique that is used to separate a solid that has not dissolved in a liquid. In this process mixture of the solid and liquid is allow to pass  through the filter paper. The clear liquid separated in the container is called the filtrate. The solid that remains in the filter paper is called the residue. Q. Why filtration is preferred over decantation? Ans:  Sometimes in decantation the liquid is not completely separated from an insoluble liquid then we  apply  the method of decanta

CBSE MATH STUDY: Factor and reminder theorem :Polynomial class IX :  Proof of this factor theorem Let  p ( x ) be a polynomial of degree greater than or equal to one and  a   be  areal number such that  p ( a... Proof of this factor theorem Let  p ( x ) be a polynomial of degree greater than or equal to one and  a   be  areal number such that  p ( a ) = 0. Then, we have to show that ( x  –  a ) is a factor of  p ( x ). Let  q ( x ) be the quotient when  p ( x ) is divided by  ( x – a ). By remainder theorem, Dividend  = Divisor x Quotient + Remainder p ( x ) = ( x – a ) x  q ( x ) +  p ( a ) [Remainder theorem] ⇒   p ( x ) = ( x – a ) x  q ( x ) [ p ( a ) = 0] ⇒  ( x – a ) is a factor of  p ( x ) Conversely, let ( x – a ) be a factor of  p ( x ). Then we have to prove that  p ( a ) = 0 Now,     ( x – a ) is a factor of  p ( x ) ⇒   p ( x ), when divided by ( x – a ) gives remainder zero.  But, by the remainder theorem,  p ( x ) when divided by ( x – a ) gives the remainde

1-mark Questions/ Answers 1. What happens when magnesium ribbon burns in air? Ans. When magnesium ribbon burns in air, it combines with the oxygen to form magnesium oxide.  2Mg(s) + O2(g) ® 2MgO(s) 2. Name the gas evolved when zinc reacts with dil. HCl. Ans. Hydrogen gas is evolved. 3. What is a chemical equation? Ans. A chemical equation is a symbolic notation that uses formulae instead of words to represent a chemical equation. 4. On what chemical law, balancing of chemical equation is based? Ans. Balancing of a chemical equation is based on the law of conservation of mass. 5. Represent decomposition of ferrous sulphate with the help of balanced chemical equation. Ans. 2FeSO4(s) ® Fe2O3(s) + SO2(g) + SO3(g) 6. When carbon dioxide is passed through lime water, it turns milky, why? Ans. Lime water (calcium hydroxide) combines with carbon dioxide to form a suspension of calcium carbonate which makes lime water milky. Ca(OH)2 + CO2 ® CaCO3 + H2O 7. A zinc r

Q. What is Nutrients? Ans: The chemical present in food is called nutrients . Q. What are major components of foods? Ans: The major components nutrients are: carbohydrates,Fats,Vitamins,Proteins,Minerals,Roughage and Water Q. What are major nutrients of foods? Ans: carbohydrates, Fats, Vitamins , Proteins and Minerals Q. Name the components of food other than nutrients that are needed by our body. Ans: Components of food other than nutrients that are needed by our body are dietary fibers and water Q. What are fats? What are its types? Ans: Fats are energy giving nutrients comes from plants and animals. Fats comes from animal are called animal fats like milk cheese, butter etc. Fats comes from plants are called vegetable fats like fruit , coconut, soya beans etc Q. How fats are use full to us? Ans: Fats give us energy. Fats also protect skin from injury, heat and cold. fats also absorb vitamins from fats soluble vitamins. Q. why we do not eat excess fats? Ans: If we eat excess fat

chemistry adda: X Formative assessments Chemical reaction and equa... : Q1. The given equation represents the reaction of sodium metal with water. Sodium + Water Sodium hydroxide + Hydrogen Which of the followin...

            (Practice) MCQ of Electricity 1.Electricity constituted by electric charges at rest on the surface of a conductor is called a. Electricity b. Potential difference c. Current electricity d. Static electricity  2.The closed path between two points at different potentials, to make the electric current flow is called a. Electric circuit b. Electric current   c. Electric potential d. Electric cell. 3. Direction of conventional current is taken from a. Negative to positive b. Positive to negative c. It could be from positive to negative or negative to positive d. None of these. 4. With increase in temperature, resistance of a conductor  a. Decreases                                                      b. Increases       c . May decreases or increases depending on temperature   d. It does not depend on temperature. 5. In series combination, resistance increases due to increase in