Life Processes — Science STD 10 — Question

What is meant by the reactivity series of metals? Arrange the following metals in an increasing order of their reactivities towards water:
Zinc, Iron, Magnesium, Sodium

Why should we conserve forests and wildlife?

How is the reflection of light ray from a plane mirror different from the refraction of light ray as it enters a block of glass?

How does the valency of elements vary (i) in going down a group, and (ii) in going from left to right in a period of the periodic table?

Why carnivores have shorter small intestine?

If a harmful chemical enters a food chain comprising snakes, hawks, mice and plants, which of these organisms is likely to have maximum concentration of the harmful chemicals in its body?

The improvement in our lifestyle has led to the generation of large amount of waste material. List two reasons to justify this statement.

Write an equation to show the reaction between Plaster of Paris and water.

Explain clearly why, a person who has lost the sight of one eye is at a disadvantage compared with the normal person who has two good eyes.

What is meant by incineration? For what purpose is it used?