Which one among the following is used in making lead pencils ?

examrobotsa's picture

Submitted by examrobotsa on

Q: 46 (CDS-I/2015)

Which one among the following is used in making lead pencils ?

question_subject: 

Science

question_exam: 

CDS-I

stats: 

0,66,9,3,66,3,3

keywords: 

{'lead pencils': [0, 0, 0, 1], 'graphite': [0, 0, 3, 9], 'carbon black': [0, 0, 3, 4], 'charcoal': [1, 1, 1, 4], 'coke': [0, 1, 0, 3]}

The correct answer is option 2, graphite. Graphite is used in making lead pencils.

Option 1, charcoal, is made by burning wood or other organic matter in a low-oxygen environment. While charcoal is commonly used for drawing and sketching, it is not typically used in making lead pencils.

Option 3, coke, is a fuel made by heating coal in the absence of air. It is primarily used as a fuel in industrial processes and is not used in making lead pencils.

Option 4, carbon black, is a fine black powder made from incomplete combustion of carbonaceous materials such as coal or oil. It is used in various applications like ink, rubber, and plastics, but it is not used in making lead pencils.

Therefore, option 2, graphite, is the correct answer as it is the main component used to create the "lead" in lead pencils. Graphite is a form of crystalline carbon that has excellent properties for writing and drawing due to its softness and ability to leave dark marks on paper.