P-1 Lenses — Science STD 10 — Question

Two exactly similar heating resistances are connected (i) in series, and (ii) in parallel, in two different circuits, one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.

Give two examples of natural macromolecules.

Things always look small on viewing through a lens. What is the nature of the lens?

What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?

What is the order of colours in a rainbow, from the outside to the inside?

When vegetable oil and tincture iodine react, the color of iodine does not change.

Name the material which is used for making the heating element of an electric iron.

Name that part of a box-type solar cooker which allows the sun’s heat rays to enter the box but does not allow inside heat to go out.

State two uses of a concave lens.

The atomic number of an element X is 8 and that of element Y is 12. Write down the symbols of the ions you would expect to be formed from their atoms.