What is timezone?
A time zone is a zone or region of the globe that contains a uniform standard time for business, social and legal purposes. Time zones also follows the boundaries of the countries and their subdivisions. A country may have single or multiple timezones. Almost all of the time zones are offset from Coordinated Universal Time (UTC) by a whole number of hours i.e. UTC−12 to UTC+14. However, some of time zones are offset by 30 or 45 minutes (for example Newfoundland Standard Time is UTC−03:30, Chatham Island Standard Time is UTC+12:45, and Indian Standard Time is UTC+05:30).
Why do not we have same time zone all over the world?
If we share same time all over the world then morning will be midday or evening or even midnight in other places of the world. Since different parts of the world have different day and night time current timezone system seems more scientific.
What is the difference between Greenwich Mean Time (GMT) and Coordinated Universal Time (UTC)?
There is no time difference between Greenwich Mean Time (GMT) and Coordinated Universal Time (UTC). However there exist differences between them. GMT is a time zone whereas UTC is a time standard.
What is daylight saving time (DST)?
Daylight saving time (DST) is the part of the year when we advance our clocks by one hour, shifting the time of day in relation to where the Sun is above Earth. In other words, during DST the "daylight" begins an hour later in the morning and lasts an hour longer in the evening. This change helps keep the hours of daylight coordinated with the time that most people are active. Proponents feel that this saves energy because in the spring and summer months more people may be outside in the evening and not using energy at home. There are, however, ongoing debates about how much energy is saved. The California Energy Commission has additional information about DST and links to several studies about its effects on energy consumption.
Why is Nepal time 45 minutes?
Nepal is 5 hours 45 minutes ahead of Coordinated Universal Time (UTC). There is no any specific reasons of being 45 minutes ahead. Not only Nepal there are other timezones with an offset of UTC with 45 minutes. The others timezones are Chatham Island Standard Time, with an offset of UTC+12:45, and the unofficial Australian Central Western Time, with an offset of UTC+08:45.
What is the meaning of abbreviations AM and PM
The full form of AM is "ante meridiem" and that of PM is "post meridiem". Both being latin words their meaning are "before noon"< and "after noon". Hence AM is used to indicate the first twelve hours of a day from midnight to midday and PM is used to indicate the second halve i.e remaining twelve hours of a day.