Structure of the Atom — Science STD 9 — Question

Which of the following do not exhibit Tyndall effect?
Starch solution, Sugar solution, Ink, Salt solution, Copper sulphate solution, Ammonium chloride solution, Fog, Smoke, Car exhausts.

What is the general name of the elements having 8 electrons in the valence shell of their atoms?

In the following Questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:

1. Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
2. The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
3. Assertion is true but the Reason is false.
4. The statement of the Assertion is false but the Reason is true.

Assertion: Medicine are easily absorbed by our body in colloidal form.
Reason: It is because they have large surface area and therefore, absorbed easily.

If action is always equal to the reaction, explain how a horse can pull a cart.

Why India cannot increase the area of cultivable land?

_________ is a method of control of pest or weed in which one living organism is used to control another living organism is used to control another living organisms.

Picks the odd one out and justify your choice by giving reasons.

Sea cucumber, Octopus, Feather star, Star fish.

Make a schematic atomic structure of Magnesium of Phosphorus. (Given number of protons of Magnesium = 12, Phosphorus = 15).

What is power?