Submitted by Prasoon Gupta on Wed, 03/05/2008 - 04:07
Average: 1 (1 vote)

10th Science

Question 1. Two students perform the experiments on series and parallel combinations of two given resistors R1 and R2 and plot the following V-I graphs.

Which of the two graphs above is (are) correctly labelled in terms of the words ‘series’ and parallel’

Justify your answer.

(2 Marks)

Question 2. A student finds the writing on the blackboard as blurred and unclear when sitting on the last desk in the classroom. He however, sees it clearly when sitting on the front desk at an approximate distance of 2m from the blackboard.

Draw ray diagrams to illustrate the formation of image of the blackboard writing by his eye-lens when he is seated at the (i) last desk (ii) front desk.

Name the kind of lens that would help him to see clearly even when he is seated at the last desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.

(3 Marks)

Question 3. An organic compound ‘A’ is widely used as a preservative in pickles and has a molecular formula C2H2O2. This compound reacts with ethanol to form a sweet smelling compound ‘B.

    (i) Identify the compound ‘A’

    (ii) Write the chemical equation for its reaction with ethanol to form compound ‘B’.

    (iii) Name the process and write chemical equation for getting compound ‘A’ back from ‘B’.

(3 Marks)


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