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  • Class 8 Science Study Material

An Educational platform for Preparation and Practice Class 8. Kidsfront provide unique pattern of learning Science with free online comprehensive study material in the form of QUESTION & ANSWER for each Chapter of Science for Class 8. This study material help Class 8, Science students in learning every aspect of Some Natural Phenomena . Students can understand Some Natural Phenomena concept easily and consolidate their learning by doing Online Practice Tests on Science,Some Natural Phenomena chapter repeatedly till they excel in Class 8, Some Natural Phenomena . Free ONLINE PRACTICE TESTS on Class 8, Some Natural Phenomena comprise of Hundreds of Questions on Some Natural Phenomena , prepared by the highly professionals team. Every repeat test of Some Natural Phenomena will have new set of questions and help students to prepare themselves for exams by doing unlimited Online Test exercise on Some Natural Phenomena . Attempt ONLINE TEST on Class 8,Science,Some Natural Phenomena in Academics section after completing this Some Natural Phenomena Question Answer Exercise.


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Some Natural Phenomena
Air is

a) A good conductor of electricity and heat.
b) A poor conductor of electricity and heat
c) A good conductor of electricity but poor conductor of heat.
d) A good conductor of heat but poor conductor of electricity.



Answer
Solution
Correct Answer Is : A poor conductor of electricity and heat
Solution Is : Under normal conditions, air acts as an insulator to the flow of electric current. Thermal conductivity in air is also very low. Therefore, air is poor conductor of heat as well as electricity.
A glass rod after being rubbed with silk is placed on the ground for sometime. If `A` in the figure below is touched by the glass rod, the gold foils will

a) Attract each other.
b) Repel each other.
c) Remain still
d) Vibrate periodically



Answer
Solution
Correct Answer Is : Remain still
Solution Is : On rubbing a glass rod with silk, it will acquire some charge. But this acquired charge will get discharged to the ground. Thus, no charge will flow to the gold foils on touching `A` with the glass rod. Therefore, there will be no force of interaction between the foils. Thus, they will remain still.
Electric current is

a) Static charges
b) Flow of charges.
c) Heat flow.
d) Accumulation of charges.



Answer
Solution
Correct Answer Is : Flow of charges.
Solution Is : The flow of electric charges constitute electric current or electricity. All the electrical appliances function owing to the flow of electric charges.
A device used to detect whether an object is charged or uncharged is

a) Seismograph.
b) Electron-microscope.
c) Electroscope
d) Ammeter.



Answer
Solution
Correct Answer Is : Electroscope
Solution Is : An electroscope has two metal foils, which repel each other when the metal supporting the two foils is touched by a charged body. If the body has no charge, the foils remain still.
Earthing is provided in buildings to protect us from

a) Damage caused by earthquakes
b) Damage caused by floods.
c) Excessive heat.
d) Electrical shocks



Answer
Solution
Correct Answer Is : Electrical shocks
Solution Is : Earthing is provided in buildings to protect us from electrical shocks due to any leakage of electrical current. Earthing is the process of transferring of charge from a charged body to the earth which can accept any amount of charge.
Separation of charges during thunderstorms is caused due to

a) Vigorous upward movement of air current.
b) Vigorous downward movement of air current
c) Vigorous upward movement of water droplets.
d) Saturation of water vapour in clouds.



Answer
Solution
Correct Answer Is : Vigorous upward movement of air current.
Solution Is : During the formation of thunderstorms, the air currents move upward, while the water droplets move downward. These vigorous movements cause separation of charges.
During the formation of thunderstorms, the air currents move upward, while the water droplets move downward. These vigorous movements cause separation of charges.

a) Negative and positive charges.
b) Negative charges of clouds.
c) Positive charges of clouds.
d) Water droplets of clouds



Answer
Solution
Correct Answer Is : Negative and positive charges.
Solution Is : During the formation of thunderstorms, the positive charges collect near the upper edges of the clouds and the negative charges accumulate near the lower edges. The positive charge also collects near the ground. When the magnitude of the accumulated charges becomes very large, air no longer resist their flow. The negative and positive charges meet; thus, producing streaks of bright light and sound.
In the figure below, `A` is

a) A conductor.
b) An insulator.
c) A semi conductor.
d) A spherical coke.



Answer
Solution
Correct Answer Is : A conductor.
Solution Is : The given figure shows an electroscope. `A` should be a conductor else, no charge will flow from a specimen to the foils. Thus, the electroscope will not be able to determine if the specimen is charged or not.
In the figure below, `A` is made up of wood. A glass rod is rubbed with silk and is placed on `A`. The two gold foils will

a) Attract each other.
b) Repel each other.
c) Remain still.
d) Vibrate periodically.



Answer
Solution
Correct Answer Is : Remain still.
Solution Is : On rubbing a glass rod with silk, it will acquire some charge. However, since `A` is made of wood, an insulator, no charge will flow to the gold foils. Therefore, there will be no force of interaction between the foils. Thus, they will remain still.
Earthquakes occur

a) All the time, at the seismic zones only.
b) Occasionally all over the earth.
c) Occasionally at the seismic zones only.
d) All the time, all over the earth.



Answer
Solution
Correct Answer Is : All the time, all over the earth.
Solution Is : Since there is continual movement of the earth`s plates, continuous disturbances occur underground. Therefore, earthquakes occur all the time, all over the earth. However, the magnitude of all the earthquakes is not very large that they can be noticed.