(a) Write the percentage of land area that was covered by forests by the end of the last century.
(b) Describe any two practices that led to deforestation.
(c) State the consequences of deforestation.
(d) Suggest a method to overcome deforestation.

List three roles of forests in conversing the environment . How do the forests get depleted ? State two consequences of deforestation on the environment .

List three roles of forests in conversing the environment . How do the forests get depleted ? State two consequences of deforestation on the environment .

Forests are lungs of our mother earth. They are so many problems due to deforestation. To overcome this what suggestions you would like to implement. Suggest any four of yours.

State the principle of working of a transformer. (b) Define efficiency of a transformer. (c ) State any two factors that reduce the efficiency of a transformer. (d) Calculate the current drawn by the primary of a 90% efficient transformer which steps down 220 V to 22 V , if the output resistance is 440 Omega .

State the principle of working of a transformer. (b) Define efficiency of a transformer. (c ) State any two factors that reduce the efficiency of a transformer. (d) Calculate the current drawn by the primary of a 90% efficient transformer which steps down 220 V to 22 V , if the output resistance is 440 Omega .

No chemical reaction takes place when granules of a rusty brown solid A re mixed with the powder of another solid B. however, when the mixture is heated, a reaction takes place between its components. One of the products C is a metal and settles down in the molten state while the other product D floats over it. it was observed that the reaction is highly exothermic. (a) What could the solids A and B be? (b) What are the products C and D most likely to be? (c) Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate tthe heat change which takes place. (d) What is the special name of such a reaction? State one use of such a reaction. (e) Name any two types of chemical reaction under which the above reaction can be classified.