Lithosphere - Study Mode

[#141] Igneous rocks are said to be acidic when they contain high proportion of ________
Correct Answer

(C) Silica

Explanation

Solution: When Igneous rocks contain high proportion of silica, they are acidic. Acid igneous rocks such as granite are less dense and have lighter colour than basic igneous rocks.

[#142] What is the cupshaped mouth of volcanoes?
Correct Answer

(C) Crater

Explanation

Solution: Crater is the cup shaped mouth of volcanoes. Whenever any volcano erupts material from the top of the cone is blown off or collapses into vent which widens the vent and this widened vent is called crater or caldera.

[#143] The cause of Earthquake is
Correct Answer

(A) Disturbances in Earth surface

Explanation

Solution: The cause of earthquake is disturbances in Earth surface. An Earthquake occurs when seismic waves are generated due to the release of energy from Earth's interior causing tremors Earth's surface.

[#144] What is the main cause of Tsunami?
Correct Answer

(C) Earthquake on Sea Surface

Explanation

Solution: Tsunamis are destructive sea waves which are generated due to Earthquakes on sea floors whereas tides are generated due to gravitational pull of Moon and Sun.

[#145] The Rift Valley is created
Correct Answer

(B) Between two rifts

Explanation

Solution: The Rift Valley is created between two rifts. When Earth's crust cracks, faulting takes place due, to tension or compression and a section of it subside or rise above the surrounding level. The subsided part between two blocks is called rift valley.