Notes

                   Electricity Charge Protons and electrons possess some charge. Proton has positive charge. Electron has negative charge. Neutron does not possess any charge. Like charges repel each other and unlike charges attract each other. Conductors and Insulators Conductors are those materials in which electrons can move freely. All metals are conductors. Insulators do not have any free electrons to move.  For example , wood and plastic. Electric Current The flow of electric charge is known as  Electric Current . It is expressed in terms of rate of flow of charges. The SI unit of electric current is Ampere (A). Direction of electric current is same as direction of positive charges and opposite to the direction of flow of negative charges. Potential Difference Work done per unit charge in taking charge from one point to another is known as  Potential Difference . The unit of potential difference is volt (V). 1V is defined as the potential difference between two points if 1 Joule

         Noteswala 2020            Life process All the processes such as respiration, nutrition, circulation, excretion etc. that are necessary for the survival of the living organisms are known as life processes. Modes of Nutrition The two most common type of nutrition are autotrophic nutrition and heterotrophic nutrition. Autotrophic Nutrition It is a type of nutrition in which inorganic materials such as carbon-dioxide, is used up to synthesize organic food by a process known as photosynthesis. For example, green plants use autotrophic mode of nutrition. Organisms which uses autotrophic mode of nutrition are known as autotrophs. Now the question arises how autotrophic nutrition occurs in plants using photosynthesis? For the photosynthesis to occur, carbon-dioxide, water, sunlight and chlorophyll are the required raw materials. Sunlight provides energy, chlorophyll is used to absorb the sunlight, carbon-dioxide is reduced to carbohydrates and water is oxidized to release the oxygen.

Noteswala 2020 Best questions related to chemical reaction and equation for revision for class 10   1. Why do we need to balance a chemical equation ? Answer: We need to balance a chemical equation to satisfy the law of conservation of mass. 2. Name two salts that are used in black and white photography. Answer: Two salts that are used in black and white photography are: (i) Silver chloride (ii) Silver bromide 3. What is the product formed on adding quick lime to water? Answer: When quick lime (CaO) is added to water, the product formed is slaked lime Ca(OH) 2  . 4. Write the chemical formula for marble. Answer: Chemical formula for marble is CaCO 3 . 5. Which type of reaction produces insoluble salts? Answer: Precipitation reaction produces insoluble salts. 6. A silver article turns black when kept in the open for a few days. Give reason for this change. Answer: Because H 2 S gas present in the air reacts with silver forming a coating of black silver sulphide (Ag 2 S). 7. Name the phe

  Noteswala 2020 ❤𝐄𝐥𝐞𝐜𝐭𝐫𝐢𝐜𝐢𝐭𝐲❤️ 𝐈𝐌𝐏𝐎𝐑𝐓𝐀𝐍𝐓 𝐐𝐔𝐄𝐒.... 1.  What is the difference between a conductor and an insulator? 2.  What is the difference between open and closed circuits? Draw diagrams  for both. 3.  Define parallel connection and series connection. 4.  What are the disadvantages of heating effect of current? 5.  What are the advantages of heating effect of current? 6.  What is electric current? 7.  What is potential difference? Give its unit with definition. 8.  Find the expression for calculating heat. 9.  A wire is 1m long, 0.2mm in diameter and has resistance of 10Ω. Calculate its resistivity. 10.  Calculate the area of cross section of a wire of length 2m, its resistance is 25Ω and the resistivity of material of wire is 1.84*10-6 Ωm. 11.  Calculate the energy consumed by 120W toaster in 20 minutes. 12.  What is resistance of conductors? Name two metals which are highly resistant. 13.  Why is tungsten metal used in bulbs but not in fuse wires? 14.  Def