# Solved papers for 10th Class Science Solved Paper - Science-2017 Outside Delhi Set-III

### done Solved Paper - Science-2017 Outside Delhi Set-III

• question_answer1) Write the molecular formula of the 2nd and 3rd member of the homologous series where the first member is ethyne.

• question_answer2) Why is variation important for a species?

 In the following food chain, 20,000 J of energy was available to the plants. How much energy would be available to man in this chain? Plants $\to$ Sheep $\to$ Man

• question_answer4) You being an environmentalist are interested in contributing towards the conservation of natural resources. List four activities that you can do on your own.

• question_answer5) Why are coal and petroleum categorised as natural resources? Give a reason as to why they should be used judiciously.

• question_answer6) What is periodicity in properties of elements with reference to the Modern Periodic Table? Why do all the elements of the same group have similar properties? How does the tendency of elements to gain electrons change as we move from left to right in a period? State the reason of this change.

• question_answer7) Write the electronic configuration of two elements X and Y whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element X reacts with product and also state the nature of the bond formed between both the elements.

• question_answer8) What is an organic evolution? It cannot be equated with progress. Explain with the help of a suitable example.

• question_answer9) List the two types of reproduction. Which one of the two is responsible for bringing in more variations in its progeny and how?

• question_answer10) What is "dispersion of white light"? Draw a labelled diagram to illustrate the recombination of the spectrum of white light. Why is it essential that the two prisms used for the purpose should be identical and placed in an inverted position with respect to each other?