Some Natural Phenomena Test - 6

An earthquake is a sudden shaking or trembling of earth. It is so sudden that it cannot be predicted in advance.

The seismic or fault zones are most prone to earthquakes.

The power of an earthquake is expressed in terms of its magnitude on a scale called Richter scale.

In India, earthquakes most likely occur in Gujarat.

The jumping of electrons between the two patches of clouds bearing different charges results in a big spark. The spark is seen as a flash of lightning.

Like charges repel and unlike charges attract each other.

Lightning affects radio and T.V. signals resulting in the disturbance in the sound and picture clarity. It also affects the telephone wires and cause death of people when sparks of lightning fall on them.

(A), (B) and (C) list out the uses of lightning.

The energy contained in the gaseous form (vapour) is more than the energy contained in the liquid form (water). Therefore, when vapour changes to water it loses some heat.

A glass rod when rubbed with silk acquires positive charge.

On the earth, the outer most layer "lithosphere" includes the crust and the mantle. It is fragmented into tectonic plates, which move independently relative to one another. This movement of lithospheric plates is described as plate tectonics.

Richter scale is not a linear scale. It is a logarithmic scale. A difference in magnitude of 2' implies a multiplication factor of 100.

The outer layer of the earth, on which we live is called the crust. The thickest part of the earth's crust is the continent.

An earthquake is usually caused by the movement of earth's plates. Apart from this, it is also caused by a meteor hitting the earth, volcanic eruption and underground nuclear explosion.

The way a rock responds to stress depends on its temperature, the speed of stress applied and the confining pressure on the rock.