TEASER - 05
POINT OR PERIOD
If, Year 2001 to year 2005 is equal to 5 years, January (01) to May (05) is equal to 5 months and Monday to Friday is equal to 5 days, then, 10 AM (10 Hrs) to 02 PM (14 Hrs) is equal to how many hours?
(a) 4 hrs (b) 5 hrs (c) Both
THE EXPLANATION:
Time is a continuum phenomenon however humans have segmented them for their convenience and daily uses. Time segments are designated by various names such as hours, days, months, years etc which represent a specific time interval / period.
When we say 01 year, we actually mean a period of 12 months starting from January to December. Similarly January month means a time period having 31 days starting from day 1 and ending at 31st day of the month. Same thing applies to each week (Monday to Sunday) and each day which encompasses a time period of 24 hrs, starting from 00 hours to 24 hours.
Generally, when one says 2000 to 2001, it means 2 years comprising whole of year 2000 (12 months) and whole of year 2001 (12 months) and no fractions. On same line January to February implies whole of January and whole of February (a total of 59 days).
Any segment of a time period (say a day) has a starting point and ending point, therefore a day can not be called a day unless entire period of 24 hours is completed, similarly a year should have 12 months, else it may not be called a year.
Therefore each segment of time will qualify to be called by its name only at the end of its specified period. A decade has 10 full years, (1st to 10th year), a month has full 30 days (1st to 30th days) and a week has seven full days (1st to 7th day).
LARGE TIME INTERVAL / DIVISIONS (PERIOD)
A watch, used for day to day work, has full 12 hours (00 to 12 hrs).
DIVISIONS OF TIME INTERVAL (PERIOD) OF A DAY (01 PM to 05 PM)
When we say a match or a game will start at 01 PM or 01 hours and finish at 05 PM or 05 hours (or will last from 01 to 05 hours) it can have following meaning;
SHORT TIME PERIOD (01 to 05 HRS)
SHORT TIME PERIOD (01 to 05 HRS)
As per prevailing convention, 01 hours or 01 0’ Clock’ meant end of 01 hour (or beginning of 02 hours). It never means beginning of 01 hrs hence does not include 00 to 01 hour. However, same convention is not applied when we refer in terms of years or months. When we say that ‘so and so was a number one player from 01 year to 05 year it invariably means 5 years and includes year from 00 to 01 also.
Similar to time, space is also a continuum phenomenon and space has also been segmented for convenience and daily uses. On human scale, space is generally segmented into kilometers, meters, centimeters, feet, inches etc, horizontally as well as vertically.
For example, on a horizontal scale, whenever we say 02 inch to 06 inch it can have two meanings;
1. 02 inch to 06 inch = 04 inches (2nd inch not included)
SHORT DISTANCE (SPACE) INTERVAL (02 to 06 INCH)
2. 02 inch to 06 inch = 05 inches (2nd inch included)
SHORT DISTANCE (SPACE) INTERVAL ( 01 to 06 INCH)
On a vertical scale, measurement of a depth interval can also create similar anomaly. For example, in petroleum exploration industry, oil, which occur in rock layers, is extracted by drilling a well (8 to 10 inch diameter) deep into earth. The properties of rock layer containing oil and its depth from surface is recorded and measured by wire line logs (as shown below).
DEPTH INTERVAL OF AN OIL WELL (00 to 1000 m & 390 to 420 m)
Now, imagine that a rock layer containing oil has been found to occur between 400 m to 410 m in a well. Its thickness would be measured as 10 m (as shown above).
The depth interval of oil layer can be written in two options:
i. 400 m to 410 m = 10 m (400th m not included)
ii. 400 m to 410 m = 11 m (400th m is included)
However, in petroleum industry practice, the depth interval is generally demarcated from a point on top of layer to a point at bottom of layer. The well path is measured and marked continuously so that a point will always fall on some numeral. So if top of layer falls exactly at 400 m, its depth interval would start from a point at 400 m and downward to 410 m, hence thickness of interval, as per industry practice would be taken as 10 m and not 11 m.
Depending upon the convention and practice, one of the options can be followed provided it is qualified with a definition or explanation.
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