Question

The prefix ${10^{18}}$ is
A.Giga
B.Kilo
C.Exa
D.Nano

Answer 1

Hint:The options of the given question, giga, kilo, exa and nano; are all prefixes of the units such as metre, gram, etc. Each prefix denotes a particular value to each of the units.

Complete answer:
A quantity of a substance is defined as the number or physical amount of that substance. There are two types of quantities. They are fundamental quantities as well as derived quantities. The fundamental quantities are defined as the quantities which do not depend on any other quantity. There are seven fundamental quantities which are as follows, length, mass, time, electric current, amount of substance, luminous intensity and the thermodynamic temperature. The derived quantities are defined as the quantities which depend on the fundamental quantities or other derived quantities. The examples of fundamental quantities are force, pressure, velocity, speed, acceleration, volume, energy, etc.
The standard reference chosen to measure a physical quantity is known as a unit. A unit is accepted by everyone internationally. A unit is randomly chosen, rather depending on any reason or a system. There are systems of units which are basically the collection of units in which some units are chosen as the fundamental units of that system. MKS, CGS and FPS are examples of systems of units. MKS system is also known as SI unit system.
There are prefixes applied before units which denotes a particular numerical value. Examples of such prefixes are tera, giga, milli, exa, centi, micro, etc. The numerical value of ${10^{18}}$ is denoted by the prefix exa.

Therefore, the correct answer is option C.

Note:
The prefix giga denotes the numerical value ${10^9}$. The prefix kilo represents the numerical value ${10^3}$ while the prefix nano represents the numerical value ${10^{ - 9}}$.