CBSE Class 6th, 7th, 8th, 9th, & 10th | Help Guide | Solved Exercises | MCQs | Questions & Answers | Sample Papers
Friday, 26 April 2013
Chapter 17. STARS AND THE SOLAR SYSTEM | Science | CBSE Class VIII (8th) | Solved Exercises
Things to remember....
- The phases of the moon occur because we can see only that part of the moon which reflects the light of the Sun towards us.
- Stars are celestial bodies that emit light of their own. Our sun is also a star.
- It is convenient to express distances of stars in light years.
Saturday, 20 April 2013
Chapter 16. LIGHT | Science | CBSE Class VIII (8th) | Solved Exercises
Question 1. Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
Answer : We can not see objects in the dark room without the presence of light or a lighted object it self . We may see an object only when, the light from an object enters our eyes.
Answer : We can not see objects in the dark room without the presence of light or a lighted object it self . We may see an object only when, the light from an object enters our eyes.
Sunday, 14 April 2013
Chapter 15. SOME NATURAL PHENOMENA |Science | CBSE Class VIII (8th) | Solved Exercises
Select the correct option in Questions 1 and 2.
Question 1. Which of the following cannot be charged easily by friction?
Question 1. Which of the following cannot be charged easily by friction?
- (a) A plastic scale
- (b) A copper rod
- (c) An inflated balloon
- (d) A woolen cloth.
Monday, 8 April 2013
Chapter 14. CHEMICAL EFFECTS OF ELECTRIC CURRENT | Science | CBSE Class VIII (8th) | Solved Exercises
Things to remember....
- Some liquids are good conductors of electricity and some are poor conductors.
- Most liquids that conduct electricity are solutions of acids, bases and salts.
- The passage of an electric current through a conducting liquid causes chemical reactions.
- The resulting effects are called chemical effects of currents.
- The process of depositing a layer of any desired metal on another material, by means of electricity, is called electroplating.
Friday, 5 April 2013
Chapter 13. SOUND |Science | CBSE Class VIII (8th) | Solved Exercises
Things to remember....
- Sound is produced by vibrating objects.
- In human beings, the vibration of the vocal cords produces sound.
- Sound travels through a medium (gas, liquid or solid). It cannot travel in vacuum.
- It sends the signals to the brain. This process is called hearing.
- The number of oscillations or vibrations per second is called the frequency of oscillation.
Chapter 12. FRICTION |Science | CBSE Class VIII (8th) | Solved Exercises
Things to remember....
- Friction opposes the relative motion between two surfaces in contact. It acts on both the surfaces.
- Friction depends on the nature of surfaces in contact.
- For a given pair of surfaces friction depends upon the state of smoothness of those surfaces.
Tuesday, 2 April 2013
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