Question

According to the SI system, the standard unit of time is…………...
A. Minute
B. Hour
C. Day
D. Second

Answer 1

Hint: Time is represented with all the units given, but these units may differ from the SI unit system. SI systems have standard units for few qualities. SI unit system is different from CGS unit system.

Complete step by step answer:
The International System of Units (SI) for seven base quantities of what is now known as the International System of Quantities is a base unit which is explained by the definitive units of analysis. They are notably a basic set from which all other SI units can be derived.
The SI paltry units design a set of reciprocally independent dimensions as enforced by spatial analysis commonly employed in science and technology. The 7 base units’ description of commonly used quantities are given as below –
1) Time: Second (s).
2) Length: Metre (m).
3) Mass: Kilogram (Kg).
4) Electric current: Ampere (A).
5) Thermodynamic Temperature: Kelvin (K).
6) Amount of Substance: Mole (mol).
7) Luminous Intensity: Candela (cd).
According to the justified definition of unit of time quantity, “The day is splinted in 24 hours, every hour splinted in 60 minutes and each minute splinted in 60 seconds.” The $\dfrac 1{ (24 \times 60 \times 60)}$ part of the day is termed as second.
Historically, this day was explained as the mean solar day. This special day can be explained as the ordinary time between two consecutive circumstances of local probable solar noon.
According to the formal definition of second after 2019, “It is explained by taking the hooked numerical value of the caesium frequency $\Delta {{v}_{cs}}$ and the Hertzian configuration is equal to inverse second.”
So, the correct option is D.

Note: Always remember that the smallest measurable unit of time quantity is second. Don’t get confused with the units, usually the smallest unit of the quantity is used to represent it in the SI unit.
Generally, time is represented in hours, so students often make mistakes with option (b) and (d).
There are two systems of units, CGS and MKS. MKS is known as SI unit system. In both these systems the unit of time is seconds only.