WELCOME IN THE WORLD OF UNDERSTANDING

       1. Name the part of the human eye that helps in changing the focal length of the eye lens.         2. Name the component of white light which deviates        (i) The least and     (ii) The most while passing through a glass prism.         3. Why does the clear sky appear blue? How would the sky appear in the absence of earth’s atmosphere?      4. Why does the sun seem to rise two minutes before the actual sunrise and set two minutes after the actual        sunset? Explain with the help of labeled diagram. 5. With the help of ray diagrams, show the formation of image by                                                                        (i)     a hypermetropic eye and (ii) correction of hypermetropic eye   by using an appropriate lens      6. Draw the pattern of magnetic field lines around a current carrying straight conductor. How the strength of the    magnetic field does produced change:     (i) With the distance from the conductor?     (ii) With an in

How will you test for a gas which is liberated when HCL reacts with an active metal?   2.          What is baking powder? How does it make the cake soft and spongy?   3.        What happens chemically when quick lime is added to water?   4.         Name the gas evolved when dilute HCL reacts with Sodium hydrogen carbonate. How is it recognized? 5.        How can washing soda be obtained from baking soda? Name an industrial use of washing soda other than washing clothes. 6.        What is the difference between shop and detergent? 7.         Give reason for the following observations:    (a) The element carbon forms a very large number of compounds.   (b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame.            b. Write a chemical equation to represent what happens when hydrogen gas is passed through unsaturated hydrocarbons in the presence of nickel as a catalyst.   9.  On warming it with ethanol in the