Question

____ unit does not change with respect to space and time.
(A) Derived.
(B) Standard.
(C) Regular.
(D) Large.

Answer 1

Hint: Unit: it is any standard used for making comparison in measurements. Every physical property has its unit. Every unit is related to unique physical property. I.e. meter, inch, foot is unit of length measured.

Complete step by step solution:
To solve this problem we should know the definition of the unit system.
 Derived unit: By using $7$ base unit additionally derived from the base unit. Derived units can also represent a product of power of base units. Other $22$ derived units have its specific symbol and specific name. Such as, square meters for area, distance per unit time for speed etc.
Standard unit: International System of Units (SI), French Système International d’Unités, is the modern form of metric system of units.it is the only system which is accepted by nearly every country in the world.
The reason behind forming an international system of units is to provide the same value for measurements such as length, time, weight all over the world. So, it can vary with space and time. It will be the same.
Hence, we come to know the standard unit doesn’t change with space and time. So the answer to this question will be (b).

Hence, (b) the standard unit does not change with respect to space and time.

Additional information: We have adopted this system because of uniform use of units all over the world. So, it makes it easy to carry out transactions as well trade between any parts of the world which follow these international norms. The S.I. was established and maintained by the General Conference on weight and measure (CGPM).