Class Vii : Physics : Energy : QuestionBank

Energy


Questions

1. How to calculate work done?
2. What is the S.I unit of work?
3. Write the definition of 1 Joule.
4. Write the definition of energy.
5. Explain: Work and energy have a direct relationship.
6. When the body is said to possess the energy of 1 Joule.?
7. What are the different units of the energy and state their relations?
8. Write the definition of mechanical energy.
9. What are two forms of mechanical energy?
10. How to calculate total mechanical energy?
11. Give two examples of mechanical energy.
12. What is heat energy ? Give one example.
13. Who invented the steam engine? When?
14. What is light energy?
15. Why can't we feel the light energy?
16. Explain the relation of plants and light energy.
17. What is chemical energy?
18. Give two example of chemical energy in our life.
19. Write a note on sound energy.
20. When can we hear the sound?
21. When can a bat hear the sound?
22. What is magnetic energy?
23. Give one use of the electromagnet.
24. What is electric energy? Give example.
25. What is atomic energy?
26. Give examples of peaceful and destructive purposes of atomic energy.
27. Why atomic energy is also called nuclear energy?
28. Write the definition of potential energy. What are the short forms?
29. Give two examples of potential energy due to objects state and explain.
30. Write a note on stretched rubber catapult.
31. Write a note on the hammer and its potential energy.
32. Write uses of falling stone attached to a pulley and falling water from a height.
33. Explain the factors affecting the potential energy of a body place at a height.
34. Write the definition of the kinetic energy. What are the short forms?
35. Give three examples of kinetic energy and write short notes on them.
36. What are the factors affecting the kinetic energy?
37. Give two examples of conversion of potential energy to kinetic energy when put in use.
38. What is meant by transformation of energy?
39. Give 10 examples of conversion of energy from one form into another which you find around you in daily life.
40. State the law of conservation of energy.
41. State the law of conservation of energy for transformation between potential and kinetic energy.
42. What is hydro-energy? What is its use?
43. What is hydro-electricity?

Class VII : Chemistry: Matter And Its Composition

Matter and Its Composition

Definitions : 

Matter: Matter is anything that has mass, occupies space and can be perceived by our senses.

Mass: The quantity of matter that a body contains is known as its mass.

Volume: The space occupied by a body is called its volume. 

Atom: An atom is the smallest possible unit of matter that exhibits all the properties of that matter.  Atoms usually do not have an independent existence. 

Molecule: A molecule is the smallest unit of matter which exhibits all the properties of that kind of matter and also has an independent existence.  A molecule can be formed of the atoms of the same kind (For e.g  H_2, N₂₎ or of the different kinds ( H₂O_, CO₂).

Inter-particular or Intermolecular Space: Particles of matter have space between them. This space is called inter-particular or intermolecular space.

The intermolecular force of attraction: The force of attraction existing between the particles or molecules if matter, which holds them together is called the intermolecular force of attraction. 

Fluids: All substances that can flow are called fluids. Liquids and gases are fluids. 

Interconversion of States of Matter: It is a process by which matter changes from one state to another and back to the original state without any change in its chemical composition when conditions are changes. 

Sublimation:  It is a process in which a substance changes directly from solid state to the vapour state. 

Name two objects made up of each of the following materials:

1. Metal: Gold jewellery, iron bars
2. Wool: Sweater, scarf
3. Cloth:  Shirt, Pant
4. Plastic: Bucket, toys
5. Leather: Shoes, bags

Write a short note on Newton(N).

Newton is a standard Unit (S.I unit) of force and is denoted by letter N. It is named after Sir Issac Newton, a famous scientist in recognition of his work in classical mechanics. 

Why do particles of matter move?

The particles of matter possess kinetic energy. The kinetic energy increases with the increase in the temperature and decreases with the decrease in the temperature. Hence the movement of particles of matter increases or decreases with the increase or decrease in the temperature respectively. 

What are the three main characteristics of the particles of matter?

The three main characteristics of particles of matter are 

1. Particles of matter have space between them which is called intermolecular space.
2. Particles of matter are always in random motion.
3. Particles of matter attract each other because of the intermolecular force of attraction. 

Why liquids are called fluids?

The particles in the liquid are less tightly packed in comparison to solids. in liquids, the intermolecular force of attraction is weaker and intermolecular gaps are larger. Hence the particles are free to move within the bulk and thus liquid can flow. Therefore liquids is called fluids.

What is Sublimation and name the three substances which can go through the process of sublimation? 

Sublimation is a process in which a substance changes directly from the solid state to the vapour state. 

 Example: Camphor, naphthalene, iodine crystals, ammonium chloride etc.