Sources of Energy — Science STD 10 — Question

It is desired to obtain an erect image of an object, using concave mirror of focal length of 12cm.
Where will the image of this object be, if it is placed 24cm in front of the mirror? Draw ray diagram for this situation also to justify your answer.
Show the positions of pole, principal focus and the centre of curvature in the above ray diagrams.

With the help of a labelled diagram explain how a convex lens converges a beam of parallel light rays.

List some things that concave lens and convex mirror have in common.

Which acid is produced in our stomach? What happens if there is an excess of acid in the stomach? How can its effect be cured?

Although coal and petroleum are produced by the degradation of biomass, even then we need to conserve them. Why?

What are the major constituents of urine?

What is meant by ‘heteroatom’? Give examples. Write the names and formulae of two organic compounds containing different heteroatoms.

Draw a ray diagram to show the formation of a real magnified image by a convex lens. (In your sketch the position of object and image with respect to the principal focus of lens should be shown clearly).

What happens to the moonflower

1. During daytime, and
2. At night ? What is this phenomenon known as?

Potatoes grow well on Anhad’s farm which has soil with a pH of 5.5. Anhad decides to add lot of lime to soil so that he can grow broccoli in the same farm:

1. Do potatoes grow better in acidic or alkaline soil?
2. Does broccoli grow better in acidic or alkaline soil?