Question Discussion & Solution

All given numbers are cube except 400. 400 is a square of 20.

Concept:

In magnetic compass, a magnetic needle which always directs the North-South direction.

• The compass is an instrument used for navigation and orientation that indicates position relative to the geographical directions (or points).
• Typically, a diagram called a compass rose displays the directions to the north, south, east, and west on the compass face.

Elements of Earth's Magnetic Field:

• The magnitude and direction of the magnetic field of the earth at a place are completely given by certain quantities known as magnetic elements.

Explanation:

Earth has its own magnetic field whose poles are

• Magnetic North is in Geographical South pole.
• Magnetic South is in Geographical North Pole.
• A compass needle is a bar magnet with a pointed north pole. It is attracted to the magnetic south pole.
• Hence magnetic needle points in North Direction (Magnetic South). 

The correct answer is Vitamin B1.

Key Points

• When rice is produced and not polished it is called brown rice. 
• Brown rice is rich in Vitamin B1. 
• When brown rice is polished, rice loses many vitamins and minerals including Vitamin B1 through the bran.
• Vitamin B1 also called thiamine is an essential vitamin, a deficiency of which is known to cause beriberi.

Additional Information

The correct answer is option 4, i.e Carbon.

• Carbon forms the maximum number of compounds in the periodic table.
• Since carbon has the property of tetra valency and catenation so they can form a maximum number of compounds.
• Carbon exists in several allotropic forms. Graphite and diamond are examples of allotropes of carbon that have different properties.
• The atomic number of carbon= 6. It lies in the 14th group in the periodic table.

The correct answer is Plotter.

• The plotter is an output device producing continuous lines of different colours.

​Key Points

• Plotter
  • ​The plotter is used to draw Continuous lines.
  • A plotter is a printer that reads commands from a computer to make line drawings on paper with one or more automated pens.
  • The plotter can draw continuous point-to-point lines directly from vector graphics files or commands.
• There are a number of different types of plotters:
  • A drum plotter
    • Draws on paper wrapped around a drum which turns to produce one direction of the plot, while the pens move to provide the other direction.
  • A flatbed plotter
    • It draws on paper placed on a flat surface.
  • An electrostatic plotter
    • It is used to draw on negatively charged paper with positively charged toner.

Additional Information

• Daisy wheel printing 
  • It is an impact printing technology invented in 1970 by Dr. Andrew Gabor.
  • Used for high-quality text printing.
• Chain Printer
  • An early line printer that used type slugs linked together in a chain as its printing mechanism.
  • The chain spins horizontally around a set of hammers.
  • When the desired character is in front of the selected print column, the corresponding hammer hits the paper into the ribbon and onto the character in the chain.