Question Discussion & Solution

The correct answer is Calcium Carbonate.

Key Points

• The chief component of the nacre that constitutes the pearl is aragonite (CaCO₃).
• Nacre also contains a small amount of conchiolin, a hornlike organic substance (albuminoid) that is the main constituent of the mollusc's outer shell.
• Pearl also contains Magnesium Carbonate(MgCO₃) along with Calcium Carbonate.

Additional Information

• Calcium carbonate is a common substance found in rocks as the minerals calcite and aragonite and is the main component of eggshells, snail shells, seashells, and pearls. 
• The Molar Mass of Calcium Carbonate is 100.0869 g/mol.
• Melting point: 825 °C.

The logic followed is:

The statement talks about the company X which has decided to increase the price of its car by 10%.

conclusion I and conclusion II may or may not follow because we can not tell from the given statement that what other companies will do if company X increases the price of cars.

But other companies can't increase the price and decrease the price of cars at the same time.

They will increase or decrease the price of cars.

Hence the correct answer will be Either I or II follows.

Additional Information

• If there are two or more sentences that are used to frame a statement, then, the sentences must be interrelated, and mutual contradiction should be there.
• Do not look for truthful notions. The information provided in the statement is the only requirement for a student to answer the question. No assumptions must be made.
• Read the statement carefully and look for keywords that are common between the statement and the conclusions
• If there is more than one conclusion that is applicable to the statement, students must ensure that the conclusions they opt for have some relation with each other.

The correct answer is Concave.

Key Points

• Concave Mirror:-
  • If a hollow sphere is cut into parts and the outer surface of the cut part is painted, then it becomes a mirror with its inner surface as the reflecting surface.
  • This type of mirror is known as a concave mirror.
  • A concave mirror has a reflective surface that is curved inward and away from the light source.
  • Concave mirrors reflect light inward to one focal point.
  • Unlike convex mirrors, the image formed by a concave mirror shows different image types depending on the distance between the object and the mirror.
  • Torch lights, automobile headlights are examples of concave mirrors.
  • The mirror used by the dentists to see the teeth of the patients is also a Concave Mirror.
  • Uses of Concave Mirror:
  • Used in shaving mirrors, ophthalmoscope, astronomical telescopes, headlights, solar furnaces.

Additional Information

• Convex Mirror:-
  • If the cut part of the hollow sphere is painted from inside, then its outer surface becomes the reflecting surface.
  • This kind of mirror is known as a convex mirror.
  • A convex mirror is also known as a diverging mirror as this mirror diverges light when they strike its reflecting surface.
  • Virtual, erect, and diminished images are always formed with convex mirrors, irrespective of the distance between the object and the mirror.
  • A convex mirror is a diverging mirror in which the reflective surface bulges towards the light source.
  • They are not used to focus light as they reflect light outwards.
  • The image formed by convex mirrors is smaller than the object but gets larger as they approach the mirror.
  • Magnifying glasses, telescopes are examples of convex mirrors.
  • Uses of Convex Mirror: Inside buildings, Vehicle mirrors, Magnifying glass, Security purposes.
• Plane Mirror:-
  • A plane mirror is a flat, smooth reflective surface.
  • A plane mirror always forms a virtual image that is upright, and of the same shape and size as the object, it is reflecting.
  • A spherical mirror is a mirror that has a consistent curve and a constant radius of curvature.
  • The images formed by a spherical mirror can either be real or virtual.
  • Spherical mirrors are of two types:
    • Concave Mirror
    • Convex Mirror
  • Uses of Plane Mirror: Solar cookers, looking glass, scientific instruments, constructing periscope which is used in submarines, kaleidoscope, a toy which produces beautiful patterns, SLR camera to click photos.

Fullest is an antonym of emptiest similarly, antonym of clearest is gloomiest (means dark or poorly lit).

The correct answer is 5.

Key Points

• Livestock census is conducted in India every 5 years. 
• So far, 20 livestock censuses have been conducted.
• For the first time, livestock data were collected online in the 20^th Livestock Census.
• Advance technology has been adopted to collect data through tablet computers.

Additional Information

• The first livestock census was conducted in 1951.
• West Bengal has the highest population of livestock in India.
• The total population of Goat is 64.6 million.
• The total population of livestock in India is 535.8 million.