Extra 30 short questions and answers for the "Some Natural Phenomena" chapter:12 of Class 8 CBSE Science:-
Q: What causes lightning?
A:
Lightning is caused by the accumulation of static electric charges in clouds and the subsequent discharge between clouds or between clouds and the ground.
Q: What are like charges?
A:
Like charges are charges of the same type (both positive or both negative). They repel each other.
Q: What are unlike charges?
A:
Unlike charges are charges of opposite types (one positive and one negative). They attract each other.
Q: What is an electroscope used for?
A:
An electroscope is used to detect the presence of electric charge on a body.
Q: What causes earthquakes?
A:
Earthquakes are caused by the sudden movement of tectonic plates in the Earth's crust.
Q: What is the Richter scale?
A:
The Richter scale is used to measure the magnitude of an earthquake.
Q: What is the
epicentre
of an earthquake?
A:
The
epicentre
is the point on the Earth’s surface directly above the focus of an earthquake.
Q: What is a seismic zone?
A:
A seismic zone is an area where earthquakes are more likely to occur.
Q: What is a lightning conductor?
A:
A lightning conductor is a metallic rod installed on buildings to protect them from lightning strikes by providing a safe path for the electric discharge to the ground.
Q: What safety precautions should be taken during an earthquake?
A:
During an earthquake, take cover under a sturdy table or desk, or move to an open field away from buildings and trees.
Q: What are tremors?
A:
Tremors are small earthquakes.
Q: How are thunderstorms formed?
A:
Thunderstorms are formed by the rapid upward movement of warm, moist air, leading to the formation of cumulonimbus clouds and electric discharge.
Q: What is a cyclone?
A:
A cyclone is a large-scale air mass that rotates around a strong
centre
of low atmospheric pressure.
Q: What is the eye of a cyclone?
A:
The eye of a cyclone is the calm, low-pressure
centre
of the storm.
Q: Why are coastal areas prone to cyclones?
A:
Coastal areas are prone to cyclones due to warm ocean temperatures and low-pressure systems that form over the sea.
Q: What is static electricity?
A:
Static electricity is the
build-up
of electric charges on the surface of objects.
Q: What happens when a glass rod is rubbed with silk?
A:
When a glass rod is rubbed with silk, it acquires a positive charge.
Q: What happens when an ebonite rod is rubbed with fur?
A:
When an ebonite rod is rubbed with fur, it acquires a negative charge.
Q: What is the focus of an earthquake?
A:
The focus is the point inside the Earth where the earthquake originates.
Q: What is a fault line?
A:
A fault line is a fracture in the Earth’s crust where tectonic plates move.
Q: What is the role of water vapor in lightning formation?
A:
Water vapor in the atmosphere helps in the separation of charges within clouds, leading to lightning.
Q: What is the study of earthquakes called?
A:
The study of earthquakes is called seismology.
Q: Why should one avoid standing under a tree during lightning?
A:
Trees can conduct electricity, making them dangerous places during lightning.
Q: How does a lightning conductor protect a building?
A:
It provides a low-resistance path for the lightning to travel to the ground, preventing damage to the building.
Q: What is the effect of lightning on trees?
A:
Lightning can cause trees to catch fire or split apart.
Q: How is charge transferred during lightning?
A:
Charge is transferred during lightning through a rapid flow of electrons between areas of opposite charge.
Q: What is the relationship between warm ocean water and cyclone formation?
A:
Warm ocean water provides the energy needed for cyclones to form and intensify.
Q: What are the effects of a strong earthquake?
A:
Strong earthquakes can cause widespread destruction of buildings, landslides, and tsunamis.
Q: What are safety precautions during a thunderstorm?
A:
Stay indoors, avoid using electrical appliances, and stay away from windows
.
Q: What does a seismograph measure?
A:
A seismograph measures and records the ground motion caused by earthquakes.
