Questions

Charles Macintosh (29 December 1766 – 25 July 1843) was a Scottish chemist and inventor of waterproof fabrics.He devoted all his spare time to science, particularly chemistry, and before he was twenty resigned his clerkship to take up the manufacture of chemicals. In this he was highly successful, inventing various new processes. His experiments with one of the by-products of tar, naphtha, led to his invention of waterproof fabrics.

We know that, in computers transformation of input into output is performed by the ALU unit i.e, the Arithematic and Logical unit that performs all the logical and arithmatical operations in the CPU - Central Processing Unit.

A measuring device.

Measuring devices have feet on them to measure distance.

Qualm means feeling confused, uneasiness, very doubtful and being in worry.

Hence, among the given options, Qualm is the opposite of Confidence.

Diamond is the hardest substance available on Earth.

Diamond is the hardest substance available on Earth due to the giant molecular structure of diamond in which each carbon atom is covalently bonded to four other carbon atoms. A covalent bond is very strong and requires a large amount of energy to break itself, and diamond has many covalent bonds.