Point of Origin of Earthquake Wave is known as
- A.Epicentre.
- B.Focus.
- C.Photosphere.
- D.Seismic Zone.
Correct answer
Explanation
The correct answer is B, Focus. The focus, also called the hypocentre, is the point inside the earth where the energy of an earthquake is first released and from where its waves start.
An earthquake happens when rocks along a fault suddenly slip and release stored energy. This energy spreads out from the focus as body waves, the P waves and S waves, which travel through the interior, and as surface waves once it reaches the crust. Depending on the depth of the focus, earthquakes are called shallow, intermediate or deep-focus. The strength of an earthquake is measured on the Richter or moment magnitude scale with a seismograph.
A is wrong because the epicentre is the point on the surface directly above the focus, where the waves are felt first. C is wrong because the photosphere is the visible surface of the Sun, not a part of the earth. D is wrong because a seismic zone is a whole region classified by its risk of earthquakes, not a point of origin.
Exam tip: focus lies inside the earth, epicentre lies on the surface right above it.
Practice Questions
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- A.India
- B.Japan
- C.Canada
- D.Indonesia
Show answer
Canada has vast land and a small farming population, so it practises large-scale, mechanised commercial grain farming, not intensive subsistence farming.
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- A.Malabar Coast
- B.Garo Hills
- C.Sunderban Delta
- D.Desert Region
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Read the full explanation →The Indian Railways have gone in for qualitative improvements since independence. Which of the following have taken place in recent years ?
1. Gauge conversion
2. Track electrification
3. Automatic signals
Select the correct answer using the codes given below :
- A.1 and 2 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
Show answer
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- A.Cumulus cloud
- B.Stratus cloud
- C.Nimbus cloud
- D.Cirrus cloud
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Read the full explanation →In India, rigid and stable elevated lands, denuded rocks and series of scarps are the features of which of the following?
- A.Northern mountains
- B.Peninsular plateau
- C.Northern plains
- D.Coastal plains
Show answer
The plateau is part of the ancient Gondwana landmass, so it is a rigid, stable block worn down by long erosion.
Read the full explanation →