Some Natural Phenomena
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Lightning and Transfer of Electric Charges
SubtopicLightning and Transfer of Electric Charges under Some Natural Phenomena for Grade 8 CBSE.
Preview questions (no answers)
- 1.
What is the primary function of the gold leaves in a gold-leaf electroscope?
A.To conduct heat
B.To show the presence of charge by diverging
C.To attract light
D.To measure the weight of the charge
- 2.
An uncharged object has:
A.Only positive charges
B.Only negative charges
C.Equal number of positive and negative charges
D.No charges at all
- 3.
When air becomes a conductor during lightning, it is because:
A.Air is naturally a conductor
B.The accumulated charges become so large that air can no longer resist their flow
C.Air contains a lot of water
D.The clouds pull the air
- 4.
The lightning conductor provides a:
A.Hard path for lightning
B.Resistance to lightning
C.Low resistance path for the discharge to the ground
D.Path for the rain to flow
- 5.
A lightning conductor is used to protect tall buildings from the damaging effects of lightning. Observe the flowchart showing the sequence of components in a typical lightning conductor system. What is the primary role of the 'Metal Strip' in this process?
A.To increase the electrical resistance to slow down the lightning's speed.
B.To convert the electric energy of lightning into heat energy for the building.
C.To provide a low-resistance path for the electric discharge to reach the Earth safely.
D.To generate a powerful magnetic field that repels the thundercloud away from the building.
- 6.
A student finds that a plastic comb rubbed with dry hair attracts paper bits easily in winter, but the same experiment often fails during the rainy season. Based on the provided flowchart, why does high humidity interfere with static electricity experiments?
A.High humidity causes the paper bits to gain a positive charge automatically.
B.Moisture in the air makes the air more conductive, leading to charge leakage.
C.The plastic comb becomes a permanent magnet in the presence of water vapor.
D.Moisture increases the friction, preventing the transfer of protons between objects.
- 7.
Which of these is a non-contact method of charging a body?
A.Rubbing
B.Conduction
C.Induction
D.Friction
- 8.
Why are buildings with steel frames generally safer during a lightning strike than buildings with wooden frames?
A.Steel frames attract lightning away from the people inside.
B.Steel frames provide a low-resistance path for the lightning to reach the ground.
C.Wood is more likely to catch fire when struck by lightning.
D.Both B and C are correct.
- 9.
If a positively charged rod is used to charge an electroscope by contact, and then a negatively charged rod is brought near the disc, what happens to the leaves?
A.The leaves diverge more.
B.The leaves collapse or their divergence decreases.
C.The leaves remain in the same position.
D.The leaves fall off the rod.
- 10.
The magnitude of the charge on a gold-leaf electroscope can be estimated by:
A.The color of the gold leaves.
B.The weight of the electroscope.
C.The degree of divergence of the leaves.
D.The time it takes for the leaves to collapse.
Download the worksheet for Some Natural Phenomena - Lightning and Transfer of Electric Charges to practice offline. It includes additional chapter-level practice questions.
Lightning Safety and Lightning Conductors
SubtopicLightning Safety and Lightning Conductors under Some Natural Phenomena for Grade 8 CBSE.
Preview questions (no answers)
- 1.
Why is it said that 'Hearing thunder is a warning to rush to safety'?
A.Thunder means rain will ruin your clothes
B.Thunder always follows lightning, indicating a storm is nearby
C.The sound of thunder can damage your ears
D.Thunder clouds carry a lot of dust
- 2.
The process of transferring charge from a charged object to the Earth is called:
A.Electrification
B.Earthing
C.Induction
D.Reduction
- 3.
What is the risk of using a wired telephone during lightning?
A.The phone might explode from the sound
B.Lightning can travel through the telephone wires to the user
C.The call quality will be very poor
D.The phone battery will drain very fast
- 4.
Why is it safer to be in a low-lying area than on a hill during a thunderstorm?
A.Lightning strikes are more likely to hit elevated points
B.It is warmer in low-lying areas
C.Clouds cannot reach low-lying areas
D.There is no wind in low-lying areas
- 5.
During a thunderstorm, you hear the thunder 5 seconds after you see the lightning. This is because:
A.Sound travels much slower than light
B.Light travels much slower than sound
C.The lightning strike happened 5 minutes ago
D.Sound and light are the same thing
- 6.
What is the function of the copper wire in a lightning conductor system?
A.To store electricity for the house
B.To connect the lightning rod to the earth plate
C.To keep the building cool during the storm
D.To provide electricity to the street lights
- 7.
Why is it advised to avoid 'open' spaces like balconies and rooftops during lightning?
A.There is a risk of falling off due to wind
B.They make you a prominent target for lightning discharge
C.Rainwater on the floor is always acidic
D.The air pressure is too low in open spaces
- 8.
Which of the following materials would be the WORST choice for a lightning conductor?
A.Aluminum
B.Copper
C.Iron
D.Glass
- 9.
A person is standing in an open field and their hair starts standing on end. What does this indicate?
A.The humidity is very low.
B.A lightning strike is imminent in the immediate vicinity.
C.They are having an allergic reaction to the rain.
D.The wind is blowing at a high velocity.
- 10.
The process by which an uncharged body develops charges when a charged body is brought near it is called __________; this is how a building develops a charge before a strike.
A.Conduction
B.Friction
C.Induction
D.Radiation
Download the worksheet for Some Natural Phenomena - Lightning Safety and Lightning Conductors to practice offline. It includes additional chapter-level practice questions.
Earthquakes: Causes and Seismographs
SubtopicEarthquakes: Causes and Seismographs under Some Natural Phenomena for Grade 8 CBSE.
Preview questions (no answers)
- 1.
Earthquakes can be caused by underground nuclear explosions. This is:
A.True
B.False
C.Only possible on the Moon
D.Never happens on Earth
- 2.
What happens to the energy of seismic waves as they move further away from the focus?
A.It increases
B.It decreases
C.It stays the same
D.It turns into light
- 3.
In the context of an earthquake, what is the 'Seismology'?
A.The study of stars
B.The study of earthquakes
C.The study of plants
D.The study of oceans
- 4.
Tremors on the earth can also be caused if a ______ hits the earth.
A.Raindrop
B.Meteor
C.Airplane
D.Bird
- 5.
What provides the primary energy that drives the movement of tectonic plates?
A.Internal heat of the Earth
B.The pull of the tides
C.Solar energy
D.Wind power
- 6.
If you are in bed when an earthquake starts, what is the safest thing to do?
A.Run out of the room immediately
B.Crawl under the bed
C.Stay in bed and protect your head with a pillow
D.Hide in the closet
- 7.
A massive earthquake occurring deep under the ocean floor can displace huge volumes of water, leading to:
A.Tornadoes
B.Tsunamis
C.Hurricanes
D.Droughts
- 8.
The time difference between the arrival of P-waves and S-waves at a seismograph station is used to calculate:
A.The magnitude of the quake
B.The distance to the epicenter
C.The temperature of the focus
D.The duration of the quake
- 9.
Which of the following describes the 'subduction' process often leading to deep-focus earthquakes?
A.Two plates sliding past each other without friction
B.One plate being forced under another into the Earth's mantle
C.Two plates moving apart at a mid-ocean ridge
D.A plate breaking into two smaller plates
- 10.
An earthquake of magnitude is usually:
A.Highly destructive to large cities
B.Not even felt by most people but recorded by instruments
C.Capable of causing tsunamis
D.Associated with volcanic eruptions only
Download the worksheet for Some Natural Phenomena - Earthquakes: Causes and Seismographs to practice offline. It includes additional chapter-level practice questions.
Protection Measures against Natural Calamities
SubtopicProtection Measures against Natural Calamities under Some Natural Phenomena for Grade 8 CBSE.
Preview questions (no answers)
- 1.
Which of these is a safe action if you are outdoors during an earthquake?
A.Standing under a heavy balcony.
B.Moving to a clear, open spot away from structures.
C.Taking shelter under a large billboard.
D.Holding on to a street light pole.
- 2.
A tsunami is most likely to occur in which of the following areas?
A.In a deep forest.
B.In a desert region.
C.In coastal regions after an undersea earthquake.
D.On top of a high mountain.
- 3.
Why is it advised to keep fire-fighting equipment ready in buildings located in seismic zones?
A.Earthquakes always cause rain.
B.Earthquakes may cause short circuits leading to fires.
C.Fire helps in detecting tremors.
D.To keep the building warm during tremors.
- 4.
If you are in a public place like a cinema hall during an earthquake, you should:
A.Run towards the screen.
B.Stay in your seat and cover your head with your arms.
C.Try to jump over the seats to reach the exit.
D.Stand up and scream for help.
- 5.
Why do we see the flash of lightning before we hear the sound of thunder?
A.Thunder starts after the lightning stops
B.Light travels much faster than sound
C.Sound is absorbed by the clouds
D.Our eyes are more sensitive than our ears
- 6.
If you are indoors during an earthquake, and there is no table nearby, where should you sit?
A.Near the door so you can run out easily
B.In a corner of the room, protecting your head with your arms
C.On top of a bed
D.Near a tall bookshelf
- 7.
In a building, which of the following acts as a safety bridge to carry the electric charge of lightning to the ground safely?
A.Wooden beams
B.Lightning conductor
C.Glass windows
D.Plastic pipes
- 8.
If you are driving a car and an earthquake starts, what is the best course of action?
A.Speed up to get home faster
B.Stop the car in an open area away from buildings, trees, and overpasses, and stay inside
C.Stop the car under a bridge for protection
D.Get out of the car and run as far as possible
- 9.
What is the effect of moisture (humidity) in the air on the retention of static charge on an object?
A.Humidity helps the object retain charge longer
B.Humidity makes the air more conductive, allowing charges to leak away faster
C.Humidity has no effect on static charge
D.Humidity turns negative charges into positive ones
- 10.
Why is the seismic hazard generally lower in the center of a tectonic plate compared to its boundaries?
A.The center of the plate is made of liquid rock
B.Tectonic activity, such as plates rubbing or colliding, occurs primarily at the boundaries
C.The center of the plate is too hot for earthquakes
D.The center of the plate has no gravity
Download the worksheet for Some Natural Phenomena - Protection Measures against Natural Calamities to practice offline. It includes additional chapter-level practice questions.