geomorphology & earth landforms section 9 Practice Questions Answers Test with Solutions & More Shortcuts

Answer: (b)

The weight of a body on the earth is the amount of gravitational pull is exerted by the earth.

Similarly, there is another force exerted on a body on earth, that is the centrifugal force due to its rotation which tries to move the body away from the centre of the earth and its maximum at the equator as the velocity of rotation is maximum at the equator of the earth.

The gravitational force is balanced by the centrifugal force. With the increase in the speed of rotation of the earth, the body at the equator will come more under the influence of the centrifugal force and the weight of the body will seem to have decreased.

It is estimated that if the earth rotated 17 times faster than now then the weight of a body at the equator will measure zero.

However, there will not be any change in the weight of a body at any of the poles, since there would not be any change in the centrifugal force there due to an increase or decrease in the rotational speed of the earth.

Answer: (c)

Stromboli is called the lighthouse of the Mediterranean. Stromboli is a small island in the Tyrrhenian Sea, off the north coast of Sicily, containing one of the three active volcanoes in Italy.

Answer: (d)

The heat that caused melting in the Earth’s early history was supplied from radioactivity and a large impact event.

It appears that the Earth formed through a series of collisions with other growing objects in the solar disk, a number of which had iron cores. Each collision added iron to the core and produced a magma ocean.

The only substantial heat sources for the Earth are from the decay of radioactive elements and heat from the giant impacts of accretion. Because Earth’s radioactive elements are concentrated near the surface, heat from the source is rapidly dissipated and does not accumulate.

Answer: (a)

Deserts take up about one third (33%) of the Earth’s land surface. Hot deserts usually have a large diurnal and seasonal temperature range, with high daytime temperatures, and low nighttime temperatures (due to extremely low humidity).

In hot deserts, the temperature in the daytime can reach 45 °C/113 °F or higher in the summer and dip to 0 °C/32 °F or lower at nighttime in the winter.

Answer: (c)