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Q91. Given the densities of the following planets of our solar system, which one is likely to have the largest core?
Mercury has a very high uncompressed density for its small size, indicating it is composed of a disproportionately large iron core (~70% of its mass).
Q92. What is the correct sequence in decreasing order of magnetic susceptibility?
Magnetite is strongly ferrimagnetic (highest). Pyrrhotite is also ferrimagnetic but weaker. Haematite is antiferromagnetic (weakly magnetic). Sphalerite is diamagnetic (negative/very low susceptibility).
Q93. Compared to magnetite, hematite is:
Magnetite (Fe3O4) contains ~72.4% iron and is strongly ferrimagnetic. Hematite (Fe2O3) contains ~69.9% iron and is only weakly antiferromagnetic.
Q94. If the Earth were to have twice its present radius, without any change in its average magnetization, the magnetic field at any latitude would be:
Magnetic field strength at the surface is proportional to the dipole moment divided by Radius cubed. Dipole moment is Magnetization * Volume (which scales by R^3). The R^3 terms cancel out, meaning the field remains exactly the same.
Q95. What is the typical period of revolution of a polar-orbiting Earth satellite, orbiting at a height of ~700 km from the Earth's surface?
Low Earth Orbit (LEO) satellites typically have a period of approximately 90 to 100 minutes to complete one revolution around the Earth.
Q96. In which of the following mantle derived rocks, one is likely to find mantle xenoliths?
Kimberlites are deep-seated igneous rocks that ascend rapidly from the mantle, often carrying diamonds and mantle xenoliths to the surface.
Q97. The relationship between the period of revolution of the planets around the Sun and their distance from the Sun is given by:
Kepler's Third Law of Planetary Motion states that the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
Q98. Kepler's third law does not apply to the:
Kepler's third law of planetary motion only applies to closed orbits (elliptical or circular). Comets that do not reappear follow open, parabolic or hyperbolic trajectories.
Q99. Which of the following planets has a composition very different from that of the other three?
Jupiter is a gas giant primarily composed of hydrogen and helium, whereas Earth, Mars, and Venus are rocky (terrestrial) planets.
Q100. In the case of earthquakes, isoseismal maps are prepared for their:
Isoseismal maps connect points of equal earthquake intensity on the surface.