Cinnabar is an ore of which one of the following?
- A.Copper
- B.Zinc
- C.Mercury
- D.Manganese
Correct answer
Explanation
The correct answer is C, Mercury. Cinnabar is mercury sulphide, HgS, the chief ore from which mercury is obtained.
Cinnabar is a bright red mineral. When it is roasted in air, the sulphur burns off as sulphur dioxide and mercury vapour is released, which is then condensed into liquid metal; this is one of the simplest extractions in metallurgy. Ground cinnabar was also used for centuries as the red pigment vermilion. Mercury is the only metal that is liquid at room temperature.
A is wrong because copper comes mainly from copper pyrites (chalcopyrite), malachite and cuprite. B is wrong because the main zinc ores are zinc blende (sphalerite) and calamine. D is wrong because manganese is obtained chiefly from pyrolusite, manganese dioxide.
Exam tip: cinnabar for mercury, bauxite for aluminium, galena for lead, zinc blende for zinc, haematite for iron.
Practice Questions
View allWhich one of the following plant tissues has dead cells ?
- A.Epidermis
- B.Parenchyma
- C.Collenchyma
- D.Sclerenchyma
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Sclerenchyma cells are dead at maturity, with thick walls hardened by lignin. Sclerenchyma is the tissue that makes plants hard and stiff.
Read the full explanation →Imagine a current-carrying straight conductor with magnetic field of lines in anti-clockwise direction. Then the direction of current is determined by
- A.the Right-Hand Thumb rule and it would be in the downward direction.
- B.the Left-Hand Thumb rule and it would be in the downward direction.
- C.the Right-Hand Thumb rule and it would be in the upward direction.
- D.the Left-Hand Thumb rule and it would be in the upward direction.
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For a straight wire, the right-hand thumb rule links the current to the circular field lines around it. Hold the wire in the right hand with the thumb along the current; the curled fingers then show the direction of the magnetic field lines, which form concentric circles around the wire.
Read the full explanation →Which one of the following statements is true for sound waves propagating in air?
- A.Sound is an electromagnetic wave and transverse in nature
- B.Sound is a mechanical wave and longitudinal in nature
- C.Sound is a mechanical wave and transverse in nature
- D.Sound is an electromagnetic wave and longitudinal in nature
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Sound needs a material medium to travel, and in air its particles vibrate back and forth along the direction the wave moves.
Read the full explanation →Which one of the following is primarily responsible for conduction of current in a metal?
- A.Bound electrons
- B.Free electrons
- C.Both bound and free electrons
- D.Ions
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In a metal, the outer electrons of the atoms are not tied to any one atom and drift through the lattice when a voltage is applied, carrying the current.
Read the full explanation →Which one of the following statements is correct about the magnification of an optical microscope?
- A.Magnification increases with the increase in focal length of eyepiece
- B.Magnification increases with the increase in focal length of objective
- C.Magnification does not depend upon the focal length of eyepiece
- D.Magnification decreases with the increase in focal length of eyepiece
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A compound microscope magnifies more when both its lenses have short focal lengths. In a compound microscope the objective forms a real, enlarged image, and the eyepiece magnifies it further like a simple magnifier.
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