Question

Name and define the S.l. unit of time. How is it related to (i) minute (ii) hour, (iii) day and (iv) year?

Answer 1

We need to understand the international standard unit that is used to measure the amount of time. Knowing this we can link the other quantities that are used on different scales for the same purpose to measure the time as required in this issue.

Complete step by step answer:
We know that time is the fundamental physical quantity that helps us to understand how long or when the duration of another quantity or the comparative scale is. The second is considered to be the S.I. The Physical Quantity Time Unit. The unit 'second' is defined as the time taken to undergo 9,192,631,770 ground state transitions for Caesium-133 atoms. We have both greater and smaller time measurement scales. Below, some of them are given.
(I). Minute: The interval of time is defined to be equal to sixty seconds. It is also one-sixtieth of an hour. You can give the relationship between the minute and seconds as—
1 minute $=60$ seconds
(ii). Hour: It is characterized as a time interval equal to 60 minutes. It's also the twenty-fourth day of the day. The relationship between an hour and seconds is given as -
1 hour $=60$ minutes $\therefore 1$ hour $=3600$ seconds
(iii). Day: Once on its axis, it is time for the earth to rotate. Twenty-four hours is defined as that. One day we can relate to the seconds as if they were
1 day $=24$ hours $\Rightarrow 1$ day $=24 \times 3600$ seconds
$\therefore 1$ day $=86400$ seconds
(iv). Year: It is defined as the time taken to undergo a complete revolution of the earth around the sun. It usually consists of a normal 365 days. The year and the seconds can be related as -
1 year $=365$ days $\Rightarrow 1$ year $=365 \times 86400$ seconds
$\therefore 1$ year $=31,536,000$ seconds
So, we get the relation of the seconds with all the larger time scales.

Note: It takes three hundred and sixty-five days and one-fourth of a day for the earth to revolve around the sun. We generally neglect this one-fourth and add up the quarter to give a full day once in four years, and this year becomes the leap year.