Rocks & Minerals — Set 4
Geography · चट्टानें और खनिज · Questions 31–40 of 50
What is the most abundant metal in the Earth's crust?
Correct Answer: B. Aluminum
Aluminum is the most abundant metal in the Earth's crust. It makes up about 8% of the crust by weight. However, it is rarely found in its pure form and is usually extracted from bauxite ore.
What is the most abundant element in the Earth's crust?
Correct Answer: C. Oxygen
Oxygen is the most abundant element in the Earth's crust, constituting about 46-47% by weight. It is mostly combined with other elements like silicon to form silicate minerals. Silicon is the second most abundant element.
Which rocks are technically known as 'Primary Rocks'?
Correct Answer: D. Igneous
Igneous rocks are called Primary Rocks because they were the first to form on Earth. All other rocks (sedimentary and metamorphic) are ultimately derived from igneous materials. They form directly from cooling magma.
The Red Fort in Delhi is primarily built using which type of rock?
Correct Answer: A. Red Sandstone
The Red Fort is constructed primarily using Red Sandstone. This is a sedimentary rock widely used in Mughal architecture. Sandstone is durable and easy to carve, making it popular for monuments.
The Taj Mahal is famous for its extensive use of which rock?
Correct Answer: B. White Marble
The Taj Mahal is renowned for its structure made of white Makrana marble. Marble is a metamorphic rock prized for its beauty and ability to take a high polish. It was sourced from Rajasthan for the monument.
Black soil, ideal for cotton, is derived from the weathering of which rock?
Correct Answer: A. Basalt
Black soil is formed from the weathering of basaltic lava rocks. These soils are rich in iron, magnesium, and alumina. This soil type is famously found in the Deccan Trap region of India.
Diamond and Graphite are both allotropes of which element?
Correct Answer: D. Carbon
Both diamond and graphite are pure forms (allotropes) of the element Carbon. Their different properties arise from how the carbon atoms are bonded together. Diamond is hard, while graphite is soft and used in pencils.
On the Mohs scale of hardness, what value is assigned to Talc?
Correct Answer: B. 1
Talc is assigned the value of 1 on the Mohs scale, making it the softest standard mineral. This scale is a qualitative ordinal scale characterizing scratch resistance. Diamond is at the other end with a value of 10.
On the Mohs scale of hardness, what value is assigned to Diamond?
Correct Answer: C. 10
Diamond is assigned the maximum value of 10 on the Mohs scale. It is the hardest known natural material. This extreme hardness makes it useful for industrial cutting tools as well as jewelry.
The liquid molten rock found inside the Earth's crust is called?
Correct Answer: D. Magma
Magma is the term for molten rock stored in the Earth's crust. It is a high-temperature fluid mixture of rock, volatiles, and solids. When it breaches the surface, the name changes to lava.