CBSE Questions for Class 8 Physics Some Natural Phenomena Quiz 8 - MCQExams.com

What is meant by earthing?
  • To capture high electric sparks and moving them to ground to minimise its effect
  • To capture high electric sparks and moving them to ground to maximise its effect
  • To capture high electric sparks and moving them to cloud to minimise its effect
  • none
Rub a glass tumbler with wool. Bring an inflated charged balloon, rubbed with wool, near refill. Then
  • both balloon and tumbler will repel each other.
  • both balloon and tumbler attract each other.
  • no reaction will be observed.
  • the balloon will burst.
Which factors from below affects the frequency,distribution,strength and physical properties of lightning?
  • Ground elevation
  • latitude
  • relative humidity
  • All of the above
Buildings are more susceptible to a lightning strike because
  • they are higher than their surroundings.
  • roofs of buildings are wet in rainy season and hence become good conductors of electricity.
  • the top of the building is wet and acquires an opposite charge to a cloud passing over the top by induction.
  • All of the above.
What is the main function of lightning conductor?
  • To capture lightning stroke and conduct discharge current safely to the ground
  • To capture lightning stroke and conduct discharge current safely to the cloud
  • To capture lightning stroke and conduct discharge current safely to the building
  • None
When a glass rod is rubbed with a piece of silk cloth the rod ?
  • And the cloth both acquire positive charge.
  • Becomes positively charged while the cloth has a negative charge.
  • And the cloth both acquire negative charge.
  • Becomes negatively charged while the cloth has a positive charge.
Fill in the blank.
_______is most commonly caused by charge separation in cumulonimbus clouds, or thunderheads.
  • Strom
  • Lightning
  • Cyclone
  • Hurrican
The lightening conductor is connected to interface with ground or "earth" through
  • a cathode
  • an anode
  • an electrode
  • a semiconductor
Suppose you are in a car and it is raining heavily with thunderstorms. Then what is the best way to protect yourself from a possible lightning strike?
  • Remain in the car
  • Get out of the car and take cover under the car
  • Run to a nearby tree
  • Get out and stand under an electric pole
What types of waves are seismic waves?
  • Non-mechanical waves
  • Elastic waves
  • Mechanical waves
  • Electromagnetic waves
State whether true or false:
A spark of lightning occurs when negative charges jump from one charged cloud to another.
  • True
  • False
                      is engineered to protect an elevated structure in the event of lightning strike.
  • A lightning conductor
  • Copper wire
  • A lightening shield
  • All of the above
The lower portion of a charged cloud generally carries .............. .
  • A positive charge
  • A negative charge
  • Air
  • No charge
State whether true or false:
An instrument which records seismic waves is called seismograph.
  • True
  • False
The earth shakes when _________ occurs. 
  • Tsunami
  • Flood
  • Earthquake
  • Drought
Which of the following one must do when caught in a Thunderstorm?
  • Take shelter inside an isolated tree
  • Take shelter in a safe place like car or bus
  • Sit near a window
  • Take shelter under an umbrella with a metallic end
A cup contains $$250g$$ of water. Find the total positive charge present in the cup of water.
  • $$1.34\times { 10 }^{ 19 }C$$
  • $$1.34\times { 10 }^{ 7 }C$$
  • $$2.43\times { 10 }^{ 19 }C$$
  • $$2.43\times { 10 }^{ 7 }C$$
Which of the following Earth's plates is responsible for causing an earthquake?
  • The crust of the earth
  • The mantle of the earth
  • The inner core of the earth
  • The outer core of the earth
What kind of material should be used in an earthquake prone area?
  • heavy weight
  • conducting material
  • light weight
  • any of the above
For recording earthquake at a place, tell which instrument is used: 
  • Seismograph
  • Micrometer
  • Telegraph
  • Spectrograph
If $${ 10 }^{ 9 }$$ electrons move out of a body to another body every second, then the time required to get a total charge of $$1C$$ on the other body is then
  • $$250$$ years
  • $$100$$ years
  • $$198$$ years
  • $$150$$ years
Explore and answer :
Some children are playing in the playground. Suddenly clouds gather in the sky and there is thunder and lightning. What should they do now?
The children should_______.
Choose the correct answer.
  • Run to their houses 
  • Stand under a tree
  • Just stand at their places 
  • Squat down
If the Richter scale reading for an earthquake is less than 3.5 then what can you say about the earthquake?
  • Generally not felt but recorded
  • Often felt & rarely causes damage
  • Major earth quake causes serious damage
  • Causes major damage to poorly constructed buildigs
Spark produced in sky during a thunderstorm are called
  • Lightning
  • Electric current
  • Both A and B
  • None of these
Write T against true and F against false in the statements.
Earthquakes can be predicted in advance.
  • True
  • False
If a glass rod rubbed with silk is brought near the cap of a negatively charged electroscope, the divergence of leaves will decrease.
  • True
  • False

Following are precautions one must take in case a storm is accompanied by lightning.

i) Do not take shelter under a tree.

ii) Do not take shelter under an umbrella with a metallic end.

iii) Do not take shelter in open garages, storage sheds, etc.

iv)  Do not take shelter in a bus in the open.

Which one of these is not correct?
  • (i)
  • (ii)
  • (iii)
  • (iv)
When an ebonite rod is rubbed with fur, the electrons move from ebonite to fur.
  • True
  • False
When a comb rubbed with dry hair both comb and paper gets similarly charged. 
  • True
  • False
A glass rod rubbed with silk repels an ebonite rod rubbed with fur.
  • True
  • False
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